Small Cells, Big Problems: The Increasing Precision of Cell Site Location Information and the Need for Fourth Amendment Protections
Journal of Criminal Law and Criminology
Fourth Amendment Protections Small Cells, Big Problems: The Increasing Precision of Cell Site Location Information and the Need for
Robert M. Bloom 0 1
William T. Clark 0 1
0 This Article si brought to you for rfee and open access by Northwestern University School of Law Scholarly Commons. It has been accepted for inclusion inoJurnal of Criminal Law and Criminology by an authorized editor of Northwestern University School of Law Scholarly Commons
1 Robert M. Bloom and William T. Clark, Small Cells, Big Problems: Th e Increasing Precision of Cell Site Location Information and the Need for Fourth Amendment Protections, 106 J. Crim. L. & Criminology (2016). https://scholarlycommons.law.northwestern.edu/jclc/vol106/iss2/1
THE JOURNAL OF CRIMINAL LAW & CRIMINOLOGY
Copyright © 2017 by Robert M. Bloom and William T. Clark
Vol. 106, No. 2
Printed in U.S.A.
SMALL CELLS, BIG PROBLEMS: THE
INCREASING PRECISION OF CELL SITE
LOCATION INFORMATION AND THE NEED
FOR FOURTH AMENDMENT
ROBERT M. BLOOM* &
WILLIAM T. CLARK**
The past fifty years has witnessed an evolution in technology
advancement in police surveillance. Today, one of the essential tools of
police surveillance is something most Americans carry with them in their
pockets every day, the cell phone. Cell phones not only contain a huge
repository of personal data, they also provide continuous surveillance of a
person’s movement known as cell site location information (CSLI).
In 1986, Congress sought to provide some privacy protections to CSLI
in the Stored Communication Act.1 Although this solution may have struck
the proper balance in an age when cell phones were a mere novelty in the
hands of a comparative few, we now live in an age where, as the U.S.
Supreme Court recently recognized, cell phones could be seen “an important
feature of human anatomy.”2 In 1986, there were only an estimated 681,825
subscribers serviced by 1531, cell sites. By 2013, there were 335 million
subscribers and over 340,000 cell sites.
* Professor of Law, Boston College Law School. I wish to thank Dana Borelli of the
class of 2017 of Boston College Law School and Mark Schreiber of McDermott, Will, and
Emory LLP for their valuable assistance.
** J.D. Boston College Law School (2015). William will be clerking for Douglas
Woodlock Senior Judge U.S. District Court for the District of Massachusetts.
1 18 U.S.C. §§ 2701–2711.
2 Riley v. California, 134 S. Ct. 2473, 2484 (2014).
BLOOM & CLARK
Recently, cell phone service providers have begun to use small cell
technologies, miniature cell phone towers that can provide additional
coverage and bandwidth support to overburdened cellular networks. Small
cells, known variously as femtocells, picocells, and microcells, are already
installed throughout the United States, in particular in urban areas. As small
cells overtake traditional cell phone towers as the most common means of
transmitting cellular signals, CSLI will transform from a means of placing a
person’s phone in a general area within a matter of miles to a precise
location tracking tool charting a person’s movements down to a matter of
The late Justice Scalia in his 2001 majority opinion in Kyllo v. U.S.,3 a
case involving thermal imaging, opined that “while the technology used in
the present case was relatively crude, the rule we adopt must take account of
more sophisticated systems that are already in use or in development.”4
This Article explores the evolution of CSLI by focusing on the rise of
small cell technologies. It also canvasses decisions in the circuits involving
CSLI. It points out that the third-party exception to the Fourth Amendment is
inapplicable to CSLI. Following Justice Scalia’s admonition, we believe that
CSLI will only grow more precise as small cells infiltrate cellular networks
and we therefore adopt an approach that incorporates the Fourth
Amendment requirements for a search warrant particularly describing the place to be searched and items to be seized as well as the requirement for probable cause. Placing CSLI under the Fourth Amendment would make a major section of the Stored Communication Act unconstitutional.
3 533 U.S. 27 (2001).
4 Id. at 36.
Dissenting from the U.S. Supreme Court’s 1989 decision in Florida v.
Riley,5 Justice Brennan bemoaned the Court’s choice to allow the government
to observe a person’s home via helicopter without a warrant.6 Justice
Brennan found it cause for concern that a four justice plurality of the Court
was willing to “remove virtually all constitutional barriers to police
surveillance” using this advanced technology.7 To close his dissent, Justice
Brennan invoked one of the most powerful stories of police surveillance in
western culture: George Orwell’s 1984.8 Noting the eerie parallel between
the police surveillance methods at issue before the Court in Riley and
Orwell’s vision of government helicopters darting across the sky, Justice
Brennan quoted the description of the infamous figure that loomed over
Orwell’s dystopian world: “The black-mustachio’d face gazed down from
every commanding corner . . . . BIG BROTHER IS WATCHING YOU, the caption
said . . . .”9
From a rudimentary tape recording device10 to a sophisticated cell
phone-computer,11 the U.S. Supreme Court has struggled to balance the
Fourth Amendment’s protections against the steady technological
BLOOM & CLARK
advancements in police surveillance. The Court has confronted a wide range
of surveillance technologies, from helicopters and heat rays to beepers and
GPS trackers.12 Today, however, the greatest threat to privacy is not the latest
sophisticated government technology. It is a small rectangular box that
resides in the pocket of nearly all Americans.
As the Court observed, cell phones, given their huge storage capacity,
contain the sum of an individual’s private life including photos, bank
statements, videos, contacts, a literal trove of personal data, which the Court
has sought to protect by requiring police to obtain a warrant before searching
a cell phone.13 But besides the intimate details contained therein, cell phones
also invisibly chart the path of a person’s movements throughout his or her
day by generating what it is known as cell site location information (CSLI).14
Courts and scholars are split over whether police should obtain a warrant
before reviewing CSLI.15 Some view CSLI as blips of data generated and
owned by private companies in the course of their business operations.16
Under this view, police can review CSLI just as they could any other business
record under the third-party doctrine exception.17 Others view CSLI, when
taken all together, as a rich tapestry that reveals deeply personal details of an
individual’s life.18 Under this view, police can only review CSLI after
obtaining a warrant because people have a fundamental privacy right against
having their every movement tracked by the government despite
Because of recent evolutions in cellular network technology, CSLI will
soon paint an even more precise picture of a person’s location history.19
Cellular service providers, which have traditionally relied on large cell phone
towers to send out signals, have started to add miniature cell phone towers
known as “small cells” to their networks.20 Small cells allow service
providers to dramatically increase the number of cell towers in a particular
area.21 Although this provides many benefits to cell phone users, the
increased concentration of cell towers means that CSLI will reveal a user’s
location down to a matter of feet instead of a matter of miles.22
This Article argues that the rise of small cells in cellular networks will
make CSLI so accurate that it must fall under the Fourth Amendment’s
protection.23 Part I discusses how cell phones operate relative to the
collection of CSLI, the Fourth Amendment doctrines relevant to the
collection of CSLI, and the current statutory framework by which the
government obtains CSLI.24 Part II reviews the current split amongst courts
regarding whether the Fourth Amendment is applicable to CSLI.25 Part III
argues that the Fourth Amendment requires the government to obtain a
particularized warrant supported by probable cause before reviewing CSLI.26
Part III explains that the third-party doctrine, which has traditionally been
regarded as an exception to the Fourth Amendment, does not apply to CSLI
because people have a reasonable expectation of privacy in the detailed
location history cell phones generate, unlike the information traditionally
covered under the doctrine.27
I. A LOCATION TRACKER ON EVERY LAMPPOST: CSLI, SMALL CELLS, AND
THE FOURTH AMENDMENT
This Part provides an introduction to CSLI and the Fourth
Amendment.28 Section A explains how cell phones work and how cell
phone service providers increasingly employ small cell technologies to
operate their networks.29 Section B provides an overview of the Fourth
Amendment principles relevant to CSLI, including the U.S. Supreme
Court’s case law on location-based technologies and the third-party
doctrine.30 Section C provides an overview of the statutory limitations on
the government’s power to obtain CSLI.31
A. CSLI AND THE RISE OF SMALL CELL TECHNOLOGIES
1. Cell Phones and Traditional Cellular Networks
In December 1947, while working as an engineer in Bell Labs,
Douglas H. Ring wrote an internal memorandum with the subject: “Mobile
Telephony – Wide Area Coverage.”32 In his memorandum, Ring
envisioned “[a] highly developed mobile telephone system” that would
“ultimately be capable of providing service to a mobile unit from any part
of the country at any place in the country.”33 His system would operate by
precisely arranging radio transmitters in a hexagon honey-comb pattern,
with three transmitters placed at the corners of each hexagon.34 This would
allow for the repeated use of certain frequencies with limited interference.35
Although it would take years for technology to catch up with his
vision, Ring’s proposal provided a significant foundation for our modern
Modern cellular networks use base stations, also known as cell towers
or cell sites, arranged in Ring’s hexagon pattern to provide radio coverage
to the largest amount of space in the most efficient manner.37 Base stations
are usually equipped with three antennas that each cover 120 degrees of
area, thereby ensuring that each base station sends out signal in a complete
A cell phone connects to a base station whenever it places or receives a
call or text message.39 When a cell phone connects to the base station, it
provides the user’s telephone number as well as other information,
including the device’s International Mobile Equipment Identifier,40 a unique
number that identifies the particular cell phone (like a VIN number for
cars). The wireless service provider, which maintains the cellular network,
records which cell phone connected to the network, when it connected, and
through which base station it connected in order to bill the account
associated with that device.41 This information is known generally as
The rapid rise of smartphones and other mobile computing devices has
threatened to overload the traditional cellular network.43 In 2012,
Americans used 1.468 trillion megabytes of data annually.44 In 2014, that
number more than doubled, as Americans used 4.06 trillion megabytes of
data annually.45 Moreover, each year more and more people are turning
away from laptop and desktop computers to rely almost exclusively on their
mobile devices.46 Some predict that by 2017, mobile devices will be the
Graham I, 796 F.3d 332, 343
(4th Cir. 2015)
, reh’g en banc granted, 624 F. App’x 75
(4th Cir. 2015)
40 O’Malley, supra note 37, at 20.
41 Id. at 23.
CSLI comes in two discrete forms: real-time and historic. This Article focuses on
historic CSLI, as it is the Fourth Amendment’s application to this information that has
divided courts. See Malone, supra note 15, at 710 (discussing the difference between historic
and real-time CSLI and observing that “[a] majority of courts” have required warrants based
on probable cause for orders for real-time CSLI).
43 See CTIA-The Wireless Association Survey Shows Americans Used 26 Percent More
Wireless Data in 2014, CTIA (Jun. 17, 2015),
(stating that “[t]he year-over-year pressure of skyrocketing mobile data and device growth
highlights the need for a long-term national spectrum plan so that Americans continue to
enjoy new and innovative wireless offerings”).
44 See Mike Dano, CTIA: U.S. wireless network traffic reaches 1.468 trillion MB in
2012, FIERCE WIRELESS (May 2, 2013)
(stating that “CTIA today
released its semi-annual survey, showing that wireless network data traffic in the United
States rose 69.3 percent in 2012 from 2011. The firm said the total amount of megabytes
traveling over U.S. wireless networks in 2012 reached 1.468 trillion, up from 866.8 billion in
45 CTIA, supra note 43.
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primary generators of all Internet traffic,47 thus the need for more CSLI
locations and technology which is discussed in the next Section. In order to
address these growing capacity challenges, many service providers are
turning to small cell technologies.48
2. Small Cell Technology and the Growing Precision of CSLI
Small cells are miniature base stations that provide a small range of
cellular signal in areas that are either overburdened or underserved by
traditional cellular networks.49 Small cells typically have a range of nine
meters (about thirty feet) to several hundred meters as compared to
traditional cell towers, which cover several “tens of kilometers.”50 Small
cells can serve urban communities, where the high population density puts a
massive strain on the network, or rural communities where installing a large
base station would not be cost-effective.51 Small cells have many different
names based on their different functions and uses, including femtocells,
picocells, microcells, and metrocells.52
Femtocells are compact base stations, some about the size of a
broadband router, developed for residential use.53 For those who have poor
cell phone coverage at home, femtocells put a cell phone tower into the
home itself.54 Several major wireless networks, including Verizon and
AT&T, sell femtocells directly to consumers for use in their homes for
approximately two hundred fifty dollars.55
Picocells are another form of small cell technology developed for
commercial or public use.56 For example, picocells can be installed in
network demand locations, such as hotels, large office buildings, or even
sports arenas, in order to offload some of the demand placed on the
traditional network.57 Microcells are a similar technology more appropriate
for outdoor use.58
Finally, small cell technologies used in dense urban areas are
sometimes referred to as metrocells.59 Metrocells can address signal issues
in so-called “urban canyons”—narrow streets where tall buildings may
obstruct signal.60 Metrocells are often hidden in plain sight on city streets,
attached to streetlights, building walls, or even security camera poles.61
Given the wide variety of small cells and the different advantages they
provide, service providers have increasingly incorporated them into their
networks. In 2011, it was estimated that there were 2.3 million femtocells
in use globally.62 For 2015, industry analysts expected 4 million small cells
to ship and projected that number to reach 8 million per year by 2019.63
Verizon and AT&T are projected to add approximately 100,000 small cells
in the United States in 2016.64 According to one report, by 2020, 40% of
small cells will be deployed in hyper-dense networks, where there will be
more than 150 small cells concentrated in one square kilometer.65
Service providers have begun to partner with municipalities to install
small cells. Verizon recently announced that it would place 400 small cells
57 WHAT’S THE BIG IDEA?, supra note 46, at 3; Jeffrey Spivak, Raising the (Phone
Coverage) Bars in Commercial Buildings, URBAN LAND (May 12, 2014), http://urbanland.
how owners of commercial real estate are integrating picocells and other small cell
technologies into their buildings).
58 WHAT’S THE BIG IDEA?, supra note 46, at 3.
60 Id.; FUJISTSU, supra note 56, at 2.
61 WHAT’S THE BIG IDEA?, supra note 46, at 3; Chuck Soder, ‘Small Cells’ are One of
the Next Big Things for Carriers, CRAIN’S CLEVELAND BUSINESS (Apr. 13, 2015),
http://www.crainscleveland.com/article/20150412/SUB1/304129979/small-cells-are-one-ofthe-next-big-things-for-carriers (discussing Verizon’s placement of small cells on street
lights and utility poles in Cleveland).
62 Andrews et al., supra note 53, at 497.
63 SMALL CELL FORUM, SMALL CELLS DEPLOYMENT MARKET STATUS REPORT (2015),
64 Martha DeGrasse, Can Verizon and AT&T Deploy 100,000 New Small Cells?, RCR
(Oct. 29, 2015)
65 SMALL CELL FORUM, CROSSING THE CHASM: SMALL CELLS INDUSTRY (2015),
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on utility poles throughout San Francisco.66 Similarly, Los Angeles has
announced a partnership with Ericsson, a European telecommunications
company, to install 100 “SmartPoles,” streetlights that will incorporate
small cell technology.67 The Federal Communications Commission (FCC)
has also recently updated its rules on cellular networks to promote the
installation of small cells.68 The FCC reformed its environmental and
historic preservation rules in order to ensure that small cell technologies
would be able “to flourish, delivering more broadband service to more
The integration of small cell technologies into cellular networks will
make CSLI increasingly precise. Because CSLI generated from small cells
could reveal a cell phone user’s location to within fewer than ten feet, such
CSLI would be more accurate than location data generated from GPS
technologies, which can determine location to within only fifty feet.70
Recognizing the growing threat to privacy that CSLI presents, courts have
struggled with how to best apply both constitutional and statutory
protections to this information.
B. THE FOURTH AMENDMENT AND LOCATION TRACKING
The Fourth Amendment provides two essential protections. First, it
enshrines “[t]he right of the people to be secure . . . against unreasonable
searches and seizures.”71 Second, it limits the power of courts to grant
warrants, allowing warrants to issue only when the government establishes
“probable cause . . . and particularly describ[es] the place to be searched,
and the persons or things to be seized.”72 The particularity requirement was
designed by the Founding Fathers to combat the use of general warrants by
English Customs Officers which allowed them to search anywhere they
wanted for uncustomed goods.73
There are two different theories for determining whether a “search”
has occurred within the meaning of the Fourth Amendment: the trespass
theory and the privacy theory.74 Under the trespass theory, the government
searches only when it physically intrudes upon certain recognized property
interests.75 For many years, the trespass theory was the only way to
establish a search under the Fourth Amendment.76
In the 1967 landmark decision of Katz v. United States,77 the U.S.
Supreme Court introduced a new vision of the Fourth Amendment based
not in property rights, but in privacy rights.78 In Katz, the defendant entered
a telephone booth and called someone to place a bet.79 The government,
having installed a listening device on the telephone booth, recorded his
conversation, and Katz was later convicted of illegal gambling.80 The Court
held that recording the defendant’s conversation violated his Fourth
Amendment rights.81 Although the Court noted that the government had
not trespassed against the defendant’s property, it found that the Fourth
Amendment protects whatever information a person “seeks to preserve as
private, even in an area accessible to the public.”82 The Court was willing
to recognize the defendant’s asserted privacy right because people
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reasonably expect that, when they enter a telephone booth, their phone call
“will not be broadcast to the world.”83 The Court sought to extend the
Fourth Amendment’s protections to phone calls in telephone booths in part
because of “the vital role that the public telephone has come to play in
Concurring in Katz, Justice Harlan proposed a two-step privacy-based
test for assessing Fourth Amendment claims, which has become the modern
standard for claims brought under the privacy theory.85 First, the Court
examines whether a person has “exhibited an actual (subjective) expectation
of privacy” in the place or information at issue.86 Second, the Court decides
whether that expectation of privacy is “one that society is prepared to
recognize as ‘reasonable.’”87 If both conditions are met, then a Fourth
Amendment search has occurred and, barring an exception to the contrary, a
warrantless search of such information will be deemed improper.88 In
addition, probable cause would also be required.
The Court has struggled to determine when and where society will
recognize a reasonable expectation of privacy, particularly in the face of
technological evolutions. In a pair of 1980s cases, the Court grappled with
beeper technology, an early location-tracking tool.89 In 1983, the Court
held in United States v. Knotts that the police did not violate the defendant’s
Fourth Amendment rights by using a beeper to track his journey along
public roads from the scene of a drug purchase to an associate’s house.90
The Court observed that the same tracking could have been accomplished
through visual surveillance alone.91 The Court recognized the defendant’s
argument that such a narrow view of the Fourth Amendment would allow
“twenty-four hour surveillance of any citizen of this country . . . without
judicial knowledge or supervision.”92 But the Court found that the
surveillance at issue in this case was quite limited in duration (from one
location to another) and stated that “if such dragnet-type law enforcement
83 Id. at 352.
85 Id. at 361 (Harlan, J., concurring); see also United States v. Jones, 132 S. Ct. 945, 950
(2012) (noting how “later cases have applied the analysis of Justice Harlan’s concurrence”).
86 Katz, 389 U.S. at 361 (Harlan, J., concurring).
89 United States v. Karo, 468 U.S. 705, 707 (1984); United States v. Knotts, 460 U.S.
276, 277 (1983).
90 Knotts, 460 U.S. at 281–82.
91 Id. at 282.
92 Id. at 283.
practices . . . should eventually occur, there will be time enough then to
determine whether different constitutional principles may be applicable.”93
In 1984, the Court in United States v. Karo placed a key limitation on
the use of location-tracking technology. In Karo, just as in Knotts, the
government used a concealed beeper to track the movements of the
defendant.94 Unlike in Knotts, the government continued to monitor the
beeper after it had been placed in the defendant’s house.95 The Court found
that this in-home tracking went beyond what the government could have
visually observed from public streets, for the beeper told the government
“that a particular article is actually located at a particular time in the private
residence and is in the possession of the person or persons whose residence
is being watched.”96 To the Court, this information “reveal[ed] a critical
fact about the interior of the premises that the Government . . . could not
have otherwise obtained without a warrant.”97 Therefore, the Court held the
use of the beeper violated the defendant’s reasonable expectation of privacy
in his whereabouts while out of public sight in his home.98 It should be
pointed out that the home enjoys the greatest Fourth Amendment
Nearly thirty years later, the Court fractured over how to bring the next
generation of location-tracking technology into the Fourth Amendment’s
purview. In 2012, the Court in United States v. Jones100 unanimously found
that when the government tracked the defendant using a GPS device it
installed on his vehicle, it had “searched” the defendant within the meaning
of the Fourth Amendment.101 The majority explicitly declined to determine
whether the defendant had a reasonable expectation of privacy in the GPS
location information.102 Instead, the majority returned to the pre-Katz
trespass doctrine and emphasized the fact that the government had
physically attached the GPS device to the vehicle, holding that when “the
Government obtains information by physically intruding on a
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constitutionally protected area . . . a search has undoubtedly occurred.”103
Justice Alito took issue with the majority’s reliance on the archaic
trespass theory of the Fourth Amendment in a concurrence joined by
Justices Ginsburg, Breyer, and Kagan.104 Justice Alito asserted that Katz
“did away with” the trespass theory of the Fourth Amendment, leaving the
privacy approach as the exclusive framework.105 Justice Alito, however,
struggled to explain what amount of location tracking triggered the Fourth
Amendment’s protection by violating a defendant’s reasonable expectation
of privacy. Justice Alito noted the continued applicability of Knotts, stating
that “relatively short-term monitoring of a person’s movements on public
streets accords with expectations of privacy that our society has recognized
as reasonable.”106 But, he found that the “longer term GPS monitoring in
investigations of most offenses impinges on expectations of privacy.”107
Acknowledging the doctrinal tension of applying the Fourth Amendment in
this context, Justice Alito invited Congress to enact new regulations that
could better respond to these technological advances.108
Justice Sotomayor joined the majority opinion, but wrote separately to
discuss the consequences of precise location tracking in the modern age.109
Justice Sotomayor emphasized how location tracking through GPS
technology allowed the government to not only create “a precise,
comprehensive record of a person’s public movements that reflects a wealth
of detail about her familial, political, professional, religious, and sexual
associations,” but also to retain this record indefinitely.110 To Justice
Sotomayor, such extensive monitoring by the government “chills
associational and expressive freedoms.”111 Justice Sotomayor stated that all
of these considerations should weigh on the Court’s evaluation of the
defendant’s asserted privacy right under Katz.112
Justice Sotomayor used her concurrence to critique one of the most
controversial theories in Fourth Amendment jurisprudence: the third-party
103 Id. at 950.
104 See Jones, 132 S. Ct. at 949.
105 Id. at 959–60 (Alito, J., concurring in the judgment).
106 Jones, 132 S. Ct. at 964.
108 Id. at 963–64.
109 Id. at 954–57 (Sotomayor, J., concurring).
110 Id. at 955–56.
111 Id. at 956.
SMALL CELLS, BIG PROBLEMS
doctrine.113 The third-party doctrine establishes that one cannot have a
reasonable expectation of privacy in information that he or she has given to
a third party voluntarily.114 In 1976, the Court in United States v. Miller
held that the government did not violate the Fourth Amendment when it
obtained the defendant’s financial records held at his bank without a
warrant because the defendant had voluntarily given these records to the
bank.115 Similarly, in 1979, the Court in Smith v. Maryland held that the
government’s use of a pen register, a technology which records the phone
numbers dialed on a phone, did not violate the Fourth Amendment because
the defendant voluntarily provided the phone company with these phone
numbers by placing the call.116 In both of these cases, the Court linked the
third-party doctrine to the reasonable expectation of privacy test, observing
in Smith that “a person has no legitimate expectation of privacy in
information he voluntarily turns over to third parties.”117
In her Jones concurrence, Justice Sotomayor argued that the
thirdparty doctrine should be revisited, as she viewed the doctrine “ill suited to
the digital age.”118 Justice Sotomayor observed that in today’s world,
people disclose a great deal of information to third parties that many in
society would still likely consider private, such as “the URLs that they visit
and the e-mail addresses with which they correspond.”119 Justice
Sotomayor stated that she “would not assume that all information
voluntarily disclosed to some member of the public for a limited purpose is,
for that reason alone, disentitled to Fourth Amendment protection.”120
Finally, the Court has recently recognized the essential role cell phones
have in modern society in its 2014 decision in Riley v. California.121
Observing that cell phones “are now such a pervasive and insistent part of
daily life that the proverbial visitor from Mars might conclude they were an
important feature of human anatomy,” the Court unanimously held that the
government must obtain a warrant before searching a cell phone.122
Although the common law had allowed police to search the items on an
113 Id. at 957.
114 Smith v. Maryland, 442 U.S. 735, 743–44 (1979); United States v. Miller, 425 U.S.
435, 442 (1976); see also Hoffa v. United States, 385 U.S. 293, 301–02 (1966).
115 Miller, 425 U.S. at 442.
116 Smith, 442 U.S. at 744.
117 Smith, 442 U.S. at 743–44.
118 United States v. Jones, 132 S. Ct 945, 957 (2012) (Sotomayor, J., concurring).
121 Riley v. California, 134 S. Ct. 2473, 2494–95 (2014).
122 Id. at 2484.
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arrestee’s person for centuries, the Court found that this traditional
approach did not strike the right balance between the government’s interests
and arrestee’s privacy interests when applied to cell phones.123 Concurring
in Riley, Justice Alito again invited Congress and states to pass new
regulations on cell phone searches, asserting that legislatures may be the
better equipped to balance the competing interests at stake.124
C. THE ARCHAIC PROTECTIONS OF THE STORED COMMUNICATIONS
Along with the constitutional limitations courts have imposed on
searches assisted by modern technology, Congress has also placed limits
and established procedures for such searches. In fact, Congress and the
Court have often worked hand-in-hand to bring privacy protections to
evolving technologies. For example, in 1968, after the Court brought audio
surveillance within the purview of the Fourth Amendment in Katz,
Congress passed the Wiretap Act, which sought to regulate the government
access to the contents of traditional phone calls.125 The Act provided for
comprehensive and detailed regulations and procedures for wiretap orders.
In 1986, Congress enacted the Electronic Communications Privacy
Act, which included a subsidiary act called the Stored Communications Act
(SCA).126 Then, in 1994, Congress updated the SCA and established the
current standards governing law enforcement requests for electronic
communications.127 For historic CSLI, the SCA permits the government
access through two different court orders. First, the government may obtain
a warrant that meets the standards of both the Federal Rules of Criminal
Procedure and the Fourth Amendment.128 Under this approach, a judge
must find that there is probable cause to support the warrant.
Second, the government may obtain a court order which requires a
SMALL CELLS, BIG PROBLEMS
lower showing than probable cause.129 Although the court order is similar
to the warrant requirement of the Fourth Amendment, in that a neutral
detached judicial officer is determining the justification, the amount of
justification distinguishes it from the traditional warrant requirement.
Under § 2703(d) of the SCA, the government can obtain a court order for
CSLI if it “offers specific and articulable facts showing that are reasonable
grounds to believe that . . . the records or other information sought, are
relevant and material to an ongoing criminal investigation.”130 This
standard is based off the U.S. Supreme Court’s reasonable suspicion
standard, which originated in Terry v. Ohio.131 In Terry, the Court adopted
a lesser standard than probable cause because the intrusion, a pat-down by a
police officer, was somewhat less than an arrest132 and because at the time
the legislation was passed location data was imprecise and there were
substantially fewer cell phones. In the same way, Congress at the time
believed CSLI did not need the full protection of probable cause because
the review of CSLI did not seriously impinge on a cell phone user’s
Section 2703(d)’s standard places a less stringent burden on the
government both in its evidentiary showing and in its target. Since Terry,
courts have routinely recognized that a showing of “reasonable suspicion”
is easier to meet than a showing of probable cause.134 Moreover, because
the government must only show that the information is “relevant and
material” to the investigation, it can obtain § 2703(d) orders with a far
broader scope than a Fourth Amendment warrant, which requires
particularized descriptions of the place to be searched and the items to be
seized.135 These lower standards have allowed the government to seek out
CSLI at an alarming rate. In 2015, AT&T received 58,189 demands for
historic CSLI, while in the second half of 2015, Verizon received 20,298
demands for CSLI, two-thirds of which came from § 2703(d) orders.136
129 Id. § 2703(a).
130 Id. § 2703(d).
131 Terry v. Ohio, 392 U.S. 1, 30 (1968).
133 See In re Elec. Commc’n Serv. to Disclose, 620 F.3d 304, 314–15 (3d Cir. 2010),
(discussing how the legislative history of the SCA and its amendments show that the
government sought an “intermediate [standard] that is less stringent than probable cause”).
134 See, e.g., United States v. Cortez, 449 U.S. 411, 421 (1981).
135 Freiwald, supra note 15, at 697.
136 AT&T Transparency Report, AT&T, http://about.att.com/content/csr/home/
frequently-requested-info/governance/transparencyreport.html (last visited July 9, 2016);
Verizon Transparency Report, VERIZON,
BLOOM & CLARK
When the SCA was passed, cell phones were still very much in their
infancy. The FCC had permitted the first generation of cellular service
networks only five years before.137 In 1986, there were only an estimated
681,825 total subscriber connections in the United States serviced by 1,531
cell sites.138 In contrast, by 2013, there were over 335 million estimated
total subscriber connections, in turn serviced by 304,360 cell sites.139 Due
to this explosion in cell users and cell sites, CSLI is no longer an imprecise
means of tracking available in only a few parts of the country; CSLI has
created a dragnet surveillance system far beyond what the legislators who
enacted the SCA could have imagined.
II. AN INDIVIDUAL’S PERSONAL HISTORY OR A SERVICE PROVIDER’S
BUSINESS RECORD?: COURTS SPLIT OVER FOURTH AMENDMENT’S
APPLICATION TO CSLI.
The initial circuit courts to address the Fourth Amendment’s
application to CSLI found that the government’s warrantless review of such
information did not violate the Fourth Amendment. In 2010, the Third
Circuit Court of Appeals held that the government did not have to show
probable cause to obtain a court order for CSLI.140 The Third Circuit
distinguished CSLI from the beeper technology used in Knotts and Karo,
finding that CSLI was less precise than beeper tracking technology and
therefore did not raise the same level of privacy concerns.141 Then, in 2013,
the Fifth Circuit Court of Appeals relied on the third-party doctrine to hold
that those who use cell phones voluntarily convey their location to their
phone providers and therefore have no reasonable expectation of privacy in
the CSLI generated.142
Recently, however, courts have begun to fracture over this question.
This Part reviews the recent evolution in case law on CSLI and the Fourth
Amendment.143 Section A discusses the courts that have found that a
report/us-report/ (last visited July 9, 2016).
137 See Cellular Communications Systems Decisions, 86 F.C.C.2d 469 (1981).
138 See Cellular Telecomm. Indus. Ass’n, Annual Wireless Industry Survey Results—
December 1985 to December 2013 (2014),
140 In re Elec. Commc’n Serv. to Disclose, 620 F.3d 304, 313 (3d Cir. 2010).
141 Id. at 312.
142 In re United States for Historical Cell Site Data, 724 F.3d 600, 613–14 (5th Cir.
143 See infra notes 147–230 and accompanying text.
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warrantless review of CSLI violates the Fourth Amendment.144 Section B
discusses the courts that either have found that the Fourth Amendment does
not apply to CSLI or have yet to firmly decide.145
A. COURTS THAT HAVE HELD THAT THE FOURTH AMENDMENT
REQUIRES THE GOVERNMENT TO OBTAIN A WARRANT BEFORE
In 2014, the Eleventh Circuit Court of Appeals in United States v.
Davis (Davis I),146 became the first circuit to hold that the Fourth
Amendment requires the government to obtain a warrant before reviewing
CSLI.147 In Davis I, the government received a court order for CSLI on the
defendant, and then used that CSLI to show that the defendant had made
phone calls at the same time and location as several robberies.148 The
Eleventh Circuit held that the defendant had a reasonable expectation of
privacy in the CSLI generated from his cell phone.149 The court compared
the warrantless GPS tracking of a car in Jones to the tracking of a cell
phone through CSLI.150 The court found that tracking a cell phone can
invade a person’s privacy far more than tracking a car, for “[o]ne’s cell
phone, unlike an automobile, can accompany its owner anywhere . . .
convert[ing] what would otherwise be a private event into a public one.”151
Moreover, the Eleventh Circuit rejected the government’s argument that
CSLI was too imprecise to violate a reasonable expectation of privacy.152
To the court, even if CSLI could only reveal whether a person is near a
location, “[t]here is a reasonable privacy interest in being near the home of
a lover, or a dispensary of medication, or a place of worship, or a house of
The Eleventh Circuit also found that the third-party doctrine did not
apply because the defendant had not voluntarily conveyed his location to
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his cell phone provider.154 The court recognized that most cell phone users
would not think that their service providers both collect and, more
importantly, “store historical location information.”155 The court recounted
the prosecutor’s statement to the jury in the defendant’s trial, where he said
the defendant and his co-conspirators “probably had no idea that by
bringing their cell phones with them to these robberies they were allowing
[their cell service provider] and now all of you to follow their movements
on the days and at the times of the robberies.”156
In 2015, a divided panel of the Fourth Circuit Court of Appeals in
United States v. Graham (Graham I)157 held that the government’s
warrantless collection and review of a person’s CSLI violates the Fourth
Amendment.158 In Graham, the government received a list of the
defendant’s CSLI from July 1, 2010 through February 6, 2011, a period of
221 days.159 The Fourth Circuit noted that “[t]he Supreme Court has
recognized an individual’s privacy interests in comprehensive accounts of
her movements, in her location, and in the location of her personal property
in private spaces.”160 Applying Karo, the court found tracking through
CSLI likely revealed details about the defendant’s home on “several dozen
specific occasions,” thereby invading his privacy even more than the beeper
tracking at issue in Karo.161 Then, applying Jones, the court observed that
the “privacy interests affected by long-term GPS monitoring . . . apply with
equal or greater force to historical CSLI for an extended period of time.”162
Just as the Eleventh Circuit did in Davis I, the Fourth Circuit found that cell
phones, due to their small size and increasingly inseparable relationship
with their users, allow for far more revealing tracking through private and
public areas than the tracking of cars.163
Expressing concern about the future of location tracking through
CSLI, the Fourth Circuit sought to craft a rule that could respond to
technological advancements in cellular networks. The court discussed the
154 Id. at 1217.
155 Id. (quoting In re Elec. Commc’n Serv. to Disclose, 620 F.3d 304, 317 (3d Cir. 2010)
(emphasis in original)).
157 Graham I, 796 F.3d 332
(4th Cir. 2015)
, reh’g en banc granted, 624 F. App’x 75
(4th Cir. 2015)
158 Id. at 349.
159 Graham I, 796 F.3d at 341.
160 Id. at 345.
161 Id. at 347.
162 Id. at 348.
SMALL CELLS, BIG PROBLEMS
rise of small cell technologies, including microcells and femtocells, and
“[t]he intense competition among cellular networks” to increase data
capacity.164 Because small cells will likely increase the overall accuracy of
CSLI, the court stated that it was obligated to “take such developments into
account” when evaluating surveillance through CSLI.165
The Fourth Circuit explained at length why the third-party doctrine did
not apply to CSLI.166 The court found that cell phone users do not
voluntarily convey CSLI to service providers for several reasons.167 First,
the court observed that a cell phone user “is not required to actively submit
any location-identifying information when making a call or sending a
message.”168 Instead, the service provider “automatically generates CSLI in
response to connections made between the cell phone and the provider’s
network.”169 Because cell phone users do not actively choose to disclose
their information, the court refused to find that users voluntarily disclose
their location to their network.170 According to the court, private
information only loses Fourth Amendment protection when it is disclosed
consciously and willingly.171
Second, the court focused on the important role cell phones play in
modern society. The court recognized that “for an increasing portion of our
society, [cell phone use] has become essential to full cultural and economic
participation.”172 The mere common act of using a cell phone cannot in
turn mean that people “have volunteered to forfeit expectations of
privacy.”173 Although the court accepted the legitimate business necessity
service providers have in generating CSLI, the court feared that application
of the third-party doctrine to CSLI would greatly limit the Fourth
Amendment in the modern world:
It turns out that the proliferation of cellular networks has left service providers with a
continuing stream of increasingly precise information about the locations and
movements of network users. Prior to this development, people generally had no
cause for concern that their movements could be tracked to this extent. That new
technology has happened to generate and permit retention of this information cannot
164 Id. at 350–51.
165 Id. at 351.
166 Id. at 351–61.
167 Id. at 354–56.
168 Id. at 355.
169 Graham I, 796 F.3d at 354.
172 Id. at 355–56.
173 Id. at 356.
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by itself displace our reasonable privacy expectations; nor can it justify inspection of
this information by the government in the absence of judicially determined probable
Because of these concerns, the Fourth Circuit refused to expand the
thirdparty doctrine and abrogate a cell phone user’s reasonable expectation of
privacy in their locational history.175
The dissent in Graham argued that CSLI should receive no Fourth
Amendment protection because it is governed entirely by the third-party
doctrine.176 The dissent argued that cell phone users not only convey CSLI
to service providers, but also do so voluntarily.177 The dissent reasoned that
although service providers produce the record of CSLI, it is the user who
conveys the underlying data to the service provider by using the phone.178
Moreover, the user conveys this information voluntarily because all cell
phone users know that their phone interacts with the cellular network.179
The dissent gave an example from everyday life: “[a]nyone who has
stepped outside to ‘get a signal,’ or has warned a caller of a potential loss of
service before entering an elevator, understands, on some level, that
location matters.”180 According to the dissent, because cell phone users
know that their “location matters,” they likewise know and accept that a
third party has accessed and recorded their location.181 The dissent
acknowledged the temptation of “holding that individuals always have a
reasonable expectation of privacy in large quantities of location
information, even if they have shared that information with a phone
company.”182 The dissent concluded, however, that “the third-party
doctrine does not afford us that option” because under the doctrine, “the
quantity of information an individual shares with a third party does not
affect whether that individual has a reasonable expectation of privacy.”183
Although the Ninth Circuit Court of Appeals has yet to decide whether
CSLI receives Fourth Amendment protection, several district courts from
within that circuit have extended such protection.184 In 2015, the District
SMALL CELLS, BIG PROBLEMS
Court for the Northern District of California in In re: Application for
Telephone Information Needed for a Criminal Investigation185 upheld a
magistrate order denying the government access to CSLI without obtaining
a warrant based on probable cause.186 Then, on January 7, 2016, in United
States v. Williams,187 another judge from the District Court for the Northern
District of California held that “defendants had a reasonable expectation of
privacy in the CSLI and that probable cause was necessary to obtain [a
B. COURTS THAT HAVE HELD THAT THE FOURTH AMENDMENT DOES
NOT REQUIRE WARRANTS TO REVIEW CSLI
After the decision in Davis I, the Eleventh Circuit agreed to rehear the
case en banc.189 In 2015, in United States v. Davis (Davis II),190 the en banc
court held that the government’s review of the defendant’s CSLI did not
violate the Fourth Amendment.191 First, the Eleventh Circuit found that the
CSLI related to the defendant’s cell phone was a business record owned and
generated by his service provider, MetroPCS, in which he could claim no
direct interest.192 Referring to the CSLI as “cell tower records,” the court
explained that the records “were created by MetroPCS, stored on its own
premises, and subject to its control.”193 Therefore, the court found that the
service provider had every right to comply with the government’s § 2703(d)
order and produce its business record of the defendant’s location history.194
Second, citing Miller and Smith, the court held that the defendant had
neither a subjective nor a reasonable expectation of privacy in the CSLI.195
Because “cell users know that they must transmit signals to cell towers
within range,” the court found that they know they are providing location
BLOOM & CLARK
information to their service provider, and therefore lack a subjective
expectation of privacy.196 Moreover, the court found that people cannot
have a reasonable expectation of privacy in CSLI because Smith specifically
held that people do not have a reasonable expectation of privacy in the
noncontent information generated to facilitate phone conversations.197
Although the Eleventh Circuit recognized that “the landscape of technology
has changed” since Miller and Smith, it was unwilling to depart from such
precedent simply because of these technological advances.198
After resolving the defendant’s challenge through the third-party
doctrine, the Eleventh Circuit turned to Jones.199 The Eleventh Circuit
feeling the need to distinguish Jones noted the two essential differences
between the defendant’s case and Jones: first, in the case before the court, it
was a private service provider, not the government, that collected the
location information, and second, there was no “physical intrusion on
private property” to gather this location information.200 The court went on,
however, to explain “even setting aside the controlling third-party
doctrine,” CSLI “is materially distinguishable from the precise, real-time
GPS tracking in Jones,” because CSLI cannot “identify the cell phone
user’s location with pinpoint precision.”201 Because it reveals only the
person’s general location, the court asserted that CSLI does not pose a
serious a threat to privacy.202 Obviously there are greater privacy
expectations when precise information as opposed to general information of
one’s location is implicated.
The dissent, however, noted that the government obtained sixty-seven
days’ worth of CSLI, which gave the government access to information
related to “5,803 phone calls” or “11,606 data points” on the defendant’s
location.203 Therefore, the dissent resisted applying the third-party doctrine
to the defendant’s claim because allowing the government to obtain such a
massive amount of location information without a warrant would greatly
diminish the Fourth Amendment’s protections in the modern world.204
198 Id. at 512.
199 Id. at 513.
200 Davis II, 785 F.3d at 513.
201 Id. at 515.
203 Id. at 533 (Martin, J. dissenting).
204 Id. The dissent gave the example of Google, noting that Google collects not only
direct personally identifiable information, such as a user’s name, email address, phone
number, and credit card information, but also information about a person’s Internet habits
SMALL CELLS, BIG PROBLEMS
Moving past the third-party doctrine, the dissent argued that individuals
likely have a reasonable expectation of privacy in CSLI.205 Observing that
“the subjective inquiry is easy,” the dissent argued that “people do not
expect the government to track them simply as a consequence of owning
and using what amounts to a basic necessity of twenty-first century life—
the cell phone.”206
The dissent made note of the rise of small cell technologies to rebut the
majority’s narrow view of the precision of CSLI.207 Specifically, the
dissent noted that small cells now make it impossible to know how precise
CSLI is going to be in a certain case:
As a person walks around town, particularly a dense, urban environment, her cell
phone continuously and without notice to her connects with towers, antennas,
microcells, and femtocells that reveal her location information with differing levels of
precision—to the nearest mile, or the nearest block, or the nearest foot. And since a
text or phone call could come in at any second—without any affirmative act by a cell
phone user—a user has no control of the extent of location information she reveals.208
According to the dissent, such an unlimited power to gather precise location
information about an individual must be fettered by the Fourth Amendment,
as an individual should only have such a detailed history of his or her
travels reviewed by the government after a judge has found that probable
cause justifies this invasion of privacy.209
In 2016, in United States v. Graham (Graham II),210 the en banc court
for the Fourth Circuit Court of Appeals rejected the earlier panel decision
and held that the government’s review of defendant’s CSLI did not violate
the Fourth Amendment.211 The court found that the defendant had
voluntarily turned over his location information to his service provider and
therefore, under the third-party doctrine, lost any reasonable expectation of
privacy in his CSLI.212 Although the court applied the third-party doctrine,
that, when brought together, have the potential to reveal extremely intimate details about a
person’s life. Id. at 535–36. If the third-party doctrine would allow this, then the third-party
doctrine must be revised in the light of new technology, for such deeply private information
must be protected by the Fourth Amendment. Id. at 537.
205 Id. at 538–39.
207 Id. at 541–42.
208 Davis II, 785 F.3d at 541–42.
209 Id. at 542–43.
210 United States v. Graham (Graham II), 624 Fed. App’x. 75 (2015).
211 United States v. Graham (Graham III), No. 12-4659, 2016 WL 3068018
May 31, 2016)
212 Id. at *1.
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it did recognize the uncertain state of law around CSLI, noting how “[t]he
Supreme Court may in the future limit, or even eliminate, the third-party
doctrine. Congress may act to require a warrant for CSLI. But without a
change in controlling law, we cannot conclude that the Government
violated the Fourth Amendment in this case.”213
The dissent took issue with the majority’s conclusion that the
defendant had “voluntarily conveyed” his location information at all.214 “A
customer buys a cell phone. She turns it on and puts it in her pocket. With
those acts, says the majority, she has ‘voluntarily conveyed’ an unbounded
set of personal location data to her service provider, all of which is
unprotected by the Fourth Amendment.”215 The dissent argued that under
the third-party doctrine, a defendant conveys information voluntarily only
when he has knowledge of the information and takes an affirmative action
to transmit that information to a third party.216 Applying this definition, the
dissent explained how “there is no reason to think that a cell phone user is
aware of his CSLI, or that he is conveying it.”217 Most cell phone users are
completely unaware of the fact that their service provider logs their location
not only when they make calls, but also when, as the dissent emphasized,
they passively receive calls.218 Because CSLI is generated without the
user’s knowledge and often without any accompanying affirmative act, the
dissent would have found no voluntary conveyance of information and
therefore not applied the third-party doctrine.219
In 2016, in United States v. Carpenter,220 the Sixth Circuit Court of
Appeals also held that the Fourth Amendment did not require the
government to obtain a warrant before reviewing CSLI.221 The court found
that CSLI was not private content, but was instead simply routing
information similar to “mailing addresses, phone numbers, and IP
addresses” that service providers use to facilitate phone calls.222 Applying
the third-party doctrine, the court relied heavily on Smith and found no
material difference from the phone numbers collected in Smith and the
213 Id. at *2.
214 Id. at *15 (Wynn, J., dissenting).
216 Graham III, 2016 WL 3068018, at *17.
217 Id. at *18.
218 Id. at *18–19.
219 Id. at *18.
220 United States v. Carpenter, Nos. 14–1572, 14–1805, 2016 WL 1445183
Apr. 13, 2016)
221 Id. at *1, *5.
222 Id. at *4.
SMALL CELLS, BIG PROBLEMS
CSLI at issue.223
The court stated that CSLI, or at least the CSLI generated given the
facts of the case before it, is far less precise than the GPS tracking from
Jones.224 The court acknowledged an amicus brief filed by the American
Civil Liberties Union, which extensively discussed the rise of small cells in
traditional cellular networks.225 However, the court ignored any concerns
regarding small cells, stating that “our task is to decide this case, not
hypothetical ones; and in this case there are no femtocells to be found.”226
The concurrence in Carpenter argued that the majority gave short
shrift to the defendant’s Fourth Amendment concerns.227 The concurrence
argued that by describing CSLI as routing information, the majority failed
to capture the privacy interests at stake in CSLI, for mailing addresses,
phone numbers, and IP addresses “do not necessarily reflect personal
location” in the way CSLI does.228 The concurrence would have compared
CSLI to location information like the GPS data in Jones.229 Although the
concurrence accepted that the CSLI at issue in this case was less accurate
than the GPS data in Jones, it recognized that it may be time “to develop a
new test to determine when a warrant may be necessary under these or
III. A RIGHT TO BE FREE FROM DRAGNET SURVEILLANCE: THE FOURTH
AMENDMENT PROTECTS A PERSON’S CSLI
This Part argues that the government must obtain a warrant before
reviewing CSLI.231 Section A argues that people have a reasonable
expectation of privacy in the location information their cell phones
generate.232 Section B explains why the third-party doctrine should not
preclude courts from giving CSLI Fourth Amendment protection.233
Section C asserts that Congress should reform the SCA to mandate probable
223 Id. at *5.
224 Id. at *6.
225 Brief for American Civil Liberties Union et al. as Amici Curiae Supporting
Defendants, United States v. Carpenter, Nos. 14–1572, 14–1805, 2016 WL 1445183
Cir. Apr. 13, 2016)
226 Carpenter, 2016 WL 1445183, at *6.
227 Carpenter, 2016 WL 1445183, at *13 (Stranch, J., concurring).
231 See infra notes 252–278 and accompanying text.
232 See infra notes 235–251 and accompanying text.
233 See infra notes 252–268 and accompanying text.
cause warrants for CSLI.234
BLOOM & CLARK
A. PEOPLE POSSESS A REASONABLE EXPECTATION OF PRIVACY IN
THEIR LOCATION HISTORY
The U.S. Supreme Court should hold that people have a reasonable
expectation of privacy in their location data generated through CSLI,
particularly as this location data grows increasingly precise. In finding that
cell phone users do not have a reasonable expectation of privacy in CSLI,
the Eleventh Circuit in Davis II asserted that CSLI “does not identify the
cell phone user’s location with pinpoint precision.”235 Although this may
have been true in a traditional cellular service network composed only of
large base stations, in a world of femtocells, picocells, SmartPoles, and
other small cell technologies, this is no longer the case.236 The more precise
the information, the greater the chance of pinpointing a user’s location.
Cell phone users, particularly those that live in dense urban environments,
may now generate CSLI that reveals their location to within a matter of
feet—not a matter of miles like under the traditional system.237
A future where the nearest base station is on the telephone pole outside
one’s home or inside the hallway of an apartment building is already here in
some American cities and will increasingly become the norm based on the
projected growth of small cell technologies.238 Courts must consider CSLI
as amplified by small cells in order to truly appreciate the threat to privacy
Under the distinction the Court formulated in Knotts and Karo, the
government’s review of CSLI will often violate a person’s reasonable
expectation of privacy by revealing information from within a person’s
home that the government “could not have otherwise obtained without a
warrant.”239 Once base stations are immediately outside or even inside a
person’s home, location information from these stations will perform the
SMALL CELLS, BIG PROBLEMS
same function that the concealed beeper did in Karo.240 CSLI will be able
to tell the government “that a particular article,” in this case a person’s cell
phone, “is actually located at a particular time in the private residence and is
in the possession of the person or persons whose residence is being
watched.”241 This is beyond the mere augmentation of regular police
surveillance permitted in Knotts; this is the “dragnet-type law enforcement
practices” of “twenty-four hour surveillance of any citizen of this
country . . . without judicial knowledge or supervision” of which the Knotts
Court warned.242 Warrantless collection of CSLI would allow the
government to track people after they have retreated into their homes, the
area granted the greatest privacy protections under the Fourth Amendment.
Looking beyond CSLI collected from within a person’s home, the
government’s review of CSLI also violates one’s reasonable expectation of
privacy under the analysis endorsed by the five Justices in Jones.243
Although Justice Alito could not draw a precise line as to when location
monitoring through advanced technology violated a person’s reasonable
expectation of privacy, he accepted that at a minimum, “longer term GPS
monitoring in investigations of most offenses impinges on expectations of
privacy” because people do not reasonably expect their whereabouts to be
monitored for an extended period of time by law enforcement.244 The GPS
monitoring in Jones took place over twenty-eight days.245 The CSLI
monitoring in Davis II took place over sixty-seven days, generating 11,606
data points tracing the defendant’s location,246 while the CSLI monitoring in
Graham took place over 221 days.247 It would be shocking if the CSLI
monitoring at issue in both of these cases failed to meet the standard of
long-term location monitoring that violates a person’s reasonable
expectation of privacy.
Moreover, even shorter-term monitoring may violate the theory of
240 See id.
242 United States v. Knotts, 460 U.S. 276, 284 (1983).
243 See United States v. Jones, 132 S. Ct. 945, 954–55 (2012) (Sotomayor, J.,
concurring) (accepting that long-term GPS monitoring would violate a person’s reasonable
expectation of privacy); id. at 964 (Alito, J., concurring in the judgment) (stating that GPS
surveillance of longer than four weeks violates a person’s reasonable expectation of
244 Jones, 132 S. Ct. at 964 (Alito, J., concurring in the judgment).
245 Id. at 948.
246 Davis II, 785 F.3d 498, 533
(11th Cir. 2015)
, cert. denied, 136 S. Ct. 479 (2015).
247 Graham I, 796 F.3d 332, 341
(4th Cir. 2015)
, reh’g en banc granted, 624 F. App’x
(4th Cir. 2015)
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reasonable expectation of privacy advanced by Justice Sotomayor in
Jones.248 According to Justice Sotomayor, all location tracking through
advanced technology granted the government the power to amass “a
precise, comprehensive record of a person’s public movements that reflects
a wealth of detail about her familial, political, professional, religious, and
sexual associations.”249 Even a relatively short period of location
monitoring through CSLI could reveal a wide array of deeply personal and
private information. The continuous and precise monitoring presents
serious issues as to whether we as a free society should accept this intrusion
by the government. Likewise, Justice Alito in his Jones concurrence
struggled to draw an exact line between long- and short-term monitoring, a
problem that has plagued the appellate courts confronting CSLI tracking as
well.250 Therefore, in order to craft a rule that gives the government proper
notice as to what actions will and will not violate the Fourth Amendment,
the Court should hold that people have a reasonable expectation of privacy
in all CSLI, regardless of the amount collected by the government.
By focusing on CSLI generated from traditional cellular networks, the
Eleventh Circuit in Davis II drastically underestimated the precision of
CSLI.251 A court that confronts tracking through CSLI must take into
account the rise of small cell technologies. And when such a court
considers a future where every street lamp could be a cell tower and every
apartment, office, or public park comes equipped with its own dedicated
team of femtocells and picocells, it must find that, despite these
technological encroachments, people retain a reasonable expectation of
privacy in their movements through the day.
B. THE THIRD-PARTY DOCTRINE DOES NOT PRECLUDE PROTECTION
Having established that people have a reasonable expectation of
privacy in their CSLI, the third-party doctrine does not apply to CSLI
because cell phone users do not “voluntarily convey” their location to their
service providers. In both Miller and Smith, the defendants made an active
248 Jones, 132 S. Ct. at 955–56 (Sotomayor, J., concurring).
249 Id. at 955.
250 Id. at 964 (Alito, J., concurring in the judgment); Graham I, 796 F.3d at 350 (holding
that “the government engages in a Fourth Amendment search when it seeks to examine
historical CSLI pertaining to an extended time period like 14 or 221 days”); Davis II, 785
F.3d at 516 (stating that CSLI of a period of 67 days did not reveal “anything close to [an]
‘intimate portrait’ of [the defendant’s] life”).
251 Davis II, 785 F.3d at 515 (“Historical cell tower location data does not identify the
cell phone user’s location with pinpoint precision . . . .”).
SMALL CELLS, BIG PROBLEMS
choice to give certain information to a third party.252 By writing checks and
making deposits, the defendant in Miller created the financial documents at
issue and voluntarily conveyed them to the bank.253 By manually punching
numbers into his telephone, the defendant in Smith actively provided the
phone company with the exact same information later used against him in a
Unlike Miller and Smith, service providers passively collect CSLI each
time a user’s phone connects to a base station. As the Fourth Circuit Court
of Appeals recognized in Graham I, a cell phone user “is not required to
actively submit any location-identifying information when making a call or
sending a message.”255 Rather, the information at issue is information that
the service provider “automatically generates . . . in response to connections
made between the cell phone and the provider’s network.”256 Although
CSLI is generated when cell phone users make the active choice to place a
phone call, CSLI is also generated when users make no active choice at all,
such as when they receive calls or text messages or, for smartphone users,
when applications connect to the network for updates.257 It is difficult to
see how users voluntarily convey anything when they receive unsolicited
calls from telemarketers or when applications built into their phone silently
update in the background.
The Eleventh Circuit Court of Appeals in Davis II incorrectly equated
a cell phone user’s vague awareness of how a cell phone functions with the
active choices the defendants made in Smith and Miller.258 In Smith, the
Court could draw a clear line from the defendant’s choice to give telephone
numbers to the phone company and the government’s later use of those
phone numbers as evidence.259 With the conveyance of CSLI, the line is far
less clear, as no service provider requires its users to manually enter their
location each time they place a call.260
Even if the U.S. Supreme Court were to find that cell phone users
voluntarily convey their location information to their service providers, the
252 See Smith v. Maryland, 442 U.S. 735, 743 (1979); United States v. Miller, 425 U.S.
435, 442 (1976).
253 See Miller, 425 U.S. at 438, 442.
254 Smith, 442 U.S. at 742–43.
255 Graham I, 796 F.3d 332, 355
(4th Cir. 2015)
, reh’g en banc granted, 624 F. App’x
(4th Cir. 2015)
256 Id. at 354.
257 See id. at 355.
258 Davis II, 785 F.3d 498, 511–12
(11th Cir. 2015)
, cert. denied, 136 S. Ct. 479 (2015).
259 Smith, 442 U.S. at 742–44.
260 Graham I, 796 F.3d at 355.
BLOOM & CLARK
Court should take up the questions Justice Sotomayor raised in Jones and
reexamine the continued viability of the third-party doctrine in the digital
age.261 The observations made by the Eleventh Circuit in Davis II and the
dissent in Graham I are not without merit. As the dissent in Graham I
observed, on some level, cell phone users who run outside when they
receive an important call do understand that in order to get a better signal
“location matters.”262 However, if the third-party doctrine allows the
government unfettered access to location data on all Americans who—at
even the most archaic level—understand that their information is accessible
to any company that provides a digital service, then as the dissent in Davis
II observed, the Fourth Amendment offers shrinking protection in the
increasing online world.263 Justice Sotomayor explained in her concurrence
in Jones that in order to participate in modern society, people must disclose
all sorts of private information, whether through accessing emails, shopping
online, or carrying a cell phone.264 Further, in Riley v. California, the Court
unanimously recognized the essential role cell phones have in the modern
The Court confronted a similar doctrinal challenge in Katz. In Katz,
rigid application of the Fourth Amendment’s trespass theory—the only
theory that existed at the time for showing a constitutional violation—
would have granted the government the power to listen in on the
defendant’s private conversation.266 The Court refused to allow old
doctrines to interfere with the core privacy protections of the Fourth
Amendment.267 Instead, the Court formulated a new approach that properly
considered “the vital role that the public telephone has come to play in
private communication.”268 Similarly, in Riley v. California, the Court
261 United States v. Jones, 132 S. Ct. at 945, 957 (2012) (Sotomayor, J., concurring).
262 Graham I, 796 F.3d 332, 383
(4th Cir. 2015)
, reh’g en banc granted, 624 F. App’x
(4th Cir. 2015)
. (Motz, J., dissenting).
263 Davis II, 785 F.3d at 537 (Martin, J., dissenting) (discussing the problems that “result
from a wooden application of the third-party doctrine” in the digital age).
264 Jones, 132 S. Ct. at 957 (Sotomayor, J., concurring).
265 Riley v. California, 134 S. Ct. 2473, 2484 (2014) (observing that cell phones are
“such a pervasive and insistent part of daily life that the proverbial visitor from Mars might
conclude they were an important feature of human anatomy”).
266 Katz v. United States, 389 U.S. 347, 351 (1967).
267 Id. (“But this effort to decide whether or not a given ‘area,’ viewed in the abstract, is
‘constitutionally protected’ deflects attention from the problem presented by this. For the
Fourth Amendment protects people, not places”) (internal citations omitted).
268 Id. at 352.
SMALL CELLS, BIG PROBLEMS
adopted a new doctrine to deal with searches incident to an arrest when the
search involves a cell phone.269
Today’s Supreme Court faces an equally important choice. If the
Court finds that the third-party doctrine stands in the way of protecting
CSLI from warrantless searches, then the Court must refashion its old
doctrine. Whether the Court finds that passive collection is different than
active disclosures, or whether it simply decides that the doctrine as a whole
must be discarded in the digital realm, it must not stand by and allow the
third-party doctrine to swallow the Fourth Amendment.
C. BRINGING THE SCA INTO THE 21ST CENTURY
Congress should also acknowledge the radical technological changes
that have occurred over the past thirty years and remove § 2703(d) orders
from the SCA. When the SCA was enacted, Congress could not possibly
have envisioned a future where cell phones were omnipresent and
inseparable from their users. Requiring only “specific and articulable facts
showing that there are reasonable grounds to believe that . . . the records or
other information sought, are relevant and material to an ongoing criminal
investigation” for a court order for CSLI270 may have made sense when the
United States had only 1,531 cell sites, as it did in 1994.271 It does not
make sense today in a country that contains millions of cell sites, through
which the government can gain access to a person’s movements within
tenfoot increments through the use of small cells.
In order to best protect location privacy in the modern world, Congress
must require prosecutors to go before a judge and make a showing of
probable cause before obtaining access to this trove of location information.
Because small cell technologies are evolving so rapidly, Congress may be
better suited than the courts to respond to these developments. Congress
should follow Justice Alito’s instruction from his concurrences in Jones and
Riley and craft comprehensive legislation that balances the competing
interests at stake in these cases.272
269 Riley v. California, 134 S. Ct. at 2494–95.
270 18 U.S.C. § 2703(d) (2012).
271 Brian L. Owsley, The Honorable, The Fourth Amendment Implications of the
Government’s Use of Cell Tower Dumps in its Electronic Surveillance, 16 U. PA. J. CONST.
L. 1, 33 (2013-2014).
272 Riley v. California, 134 S. Ct. at 2497–98 (Alito, J., concurring in part and
concurring in the judgment) (noting that “after assessing the legitimate needs of law
enforcement and the privacy interests of cell phone owners,” legislatures should be free to
“enact legislation that draws reasonable distinctions based on categories of information or
perhaps other variables. . . . Legislatures, elected by the people, are in a better position than
BLOOM & CLARK
In doing so, Congress must follow the Fourth Amendment
requirements of probable cause and particularity and demand that orders for
CSLI only issue upon probable cause and are only directed at particularized
targets whose accounts contain evidence of the crime under investigation.
The lower § 2703(d) standard follows from the reasonable suspicion
standard the U.S. Supreme Court formulated in Terry v. Ohio.273 The
Court in Terry, however, permitted this lower justification only because the
intrusion at issue—a pat-down—was minor; an officer “for the protection
of himself and others” was permitted only “to conduct a carefully limited
search of the outer clothing” of the target.274 When the government reviews
CSLI, it gains access to the precise details of a person’s movements across
a potentially vast period of time. This is far beyond the “carefully limited
search” the Terry standard authorized. Because the government’s review of
CSLI represents a large intrusion into the precise details of a person’s
movements, the government must in turn justify its search under a more
Congress must reform both components of the § 2703(d) standard.
First, it must require a showing of probable cause, not reasonable suspicion,
to obtain access to CSLI. Reasonable suspicion demands too little from the
government, as courts have routinely recognized the low showing needed to
meet the reasonable suspicion burden. Under a probable cause standard, the
government will have to present “reasonably trustworthy information . . . to
warrant a man of reasonable caution in the belief that an offense has been or
is being committed.”275 A probable cause standard will thereby ensure that
the government gathers CSLI only when it suspects a person of committing
a crime, rather than merely having information “relevant and material” to an
investigation.276 In this way, a probable cause standard gives proper
protection to the sensitive information of the general public, while still
we are to assess and respond to the changes that have already occurred and those that almost
certainly will take place in the future.”); United States v. Jones, 132 S. Ct. at 945, 964 (2012)
(“A legislative body is well situated to gauge changing public attitudes, to draw detailed
lines, and to balance privacy and public safety in a comprehensive way.”).
273 Terry v. Ohio, 392 U.S. 1, 30 (1968).
275 Brinegar v. United States, 388 U.S. 160, 175–76 (1949) (quoting Carroll v. United
States, 267 U.S. 132, 162 (1924)).
276 See Steven M. Harkins, Note, CSLI Disclosure: Why Probable Cause Is Necessary to
Protect What’s Left of the Fourth Amendment, 68 WASH. & LEE L. REV. 1875, 1902–03
(2011) (“Compared to probable cause, disclosure under the relevant and material standard is
both lower in the quantum of evidence required and broader in the individuals it can
potentially target, particularly third parties.”).
SMALL CELLS, BIG PROBLEMS
allowing the government to target suspected criminals.
Second, Congress—cognizant of the Fourth Amendment’s
particularity requirement—should allow orders for CSLI to issue only when
the government has shown that the order will reveal evidence of a crime.
By allowing the government to access CSLI if it is “relevant and material”
to its investigation, § 2703(d) allows the government access to the CSLI of
too many innocent people who may have only a tangential connection to a
criminal investigation. The Fourth Amendment was designed to prevent
legislatures from issuing general warrants that would grant government
agents the power to search and seize whatever and whomever they so
choose.277 In order to ensure that application for such orders for CSLI do
not authorize dragnet surveillance of an unknown number of people,
Congress must demand that the government explain how the CSLI sought
will reveal evidence of a crime.278
From femtocells in our homes to picocells on our streetlamps, small
cell technologies are spreading rapidly across the United States. Although
small cells will provide many benefits to consumers, they have the chance
to seriously erode privacy. The Stored Communications Act allows the
government to obtain historical cell site location information without a
Fourth Amendment warrant. Small cells will make CSLI increasingly
precise, allowing the government to chart a person’s movements down to a
matter of feet. When deciding whether CSLI receives Fourth Amendment
protection, courts must consider the cellular network of the near future,
where most towers are no longer massive antennas, but are instead no larger
than a breadbox. Therefore, courts should hold that the Fourth Amendment
requires the government to obtain a particularized warrant supported by
probable cause before it can review CSLI. Moreover, Congress should
recognize the increased privacy interests people have in CSLI and reform
the SCA to require a higher showing for court orders for CSLI. At its core,
the Fourth Amendment must prevent the government from tracking its
citizens from morning to night, through commute, work, church, and home,
for days on end, without first obtaining a particularized warrant supported
by probable cause. The rise of small cells cannot deprive the people of this
277 Brinegar, 338 U.S. at 176 (“To allow less [than probable cause] would be to leave
law-abiding citizens at the mercy of the officers’ whim or caprice.”).
278 Freiwald, supra note 15, at 696–98.
“Only time will tell whether our society will prove capable of
preserving age-old privacy protections in this increasingly networked
AND THE FOURTH AMENDMENT..................................................... 171
A. CSLI and the Rise of Small Cell Technologies......................... 172 1 . Cell Phones and Traditional Cellular Networks ................. 172 2. Small Cell Technology and the Growing Precision of
CSLI .................................................................................. 174
B. The Fourth Amendment and Location Tracking ....................... 176
C. The Archaic Protections of the Stored Communications Act .... 182
AMENDMENT'S APPLICATION TO CSLI. ........................................ 184
Require Warrants to Review CSLI ......................................... 189
FOURTH AMENDMENT PROTECTS A PERSON'S CSLI .................... 193
Location History ..................................................................... 194
B. The Third-Party Doctrine Does Not Preclude Protection.......... 196
C. Bringing the SCA into the 21st Century.................................... 199
CONCLUSION ............................................................................................. 201
12 See, e.g., United States v . Jones , 132 S. Ct . 945 , 948 ( 2012 ); Kyllo v . United States,
533 U.S. 27 , 29 ( 2001 ); Florida v . Riley , 488 U.S. at 447- 48 . 13 See Riley v. California, 134 S. Ct. at 2494-95. 14 See infra notes 39-42 and accompanying text (explaining how cell phones work and
how CSLI is created) . 15 Compare Susan Freiwald , Cell Phone Location Data and the Fourth Amendment: A
Question of Law, Not Fact, 70 MD. L. REV. 681 , 690 ( 2011 ) (arguing that CSLI should
Historical Cell Site Location Information Poses No Threat to Privacy, 39 PEPP. L. REV. 701 ,
706 ( 2012 ) (arguing that the Fourth Amendment does not require the government to obtain a
warrant before reviewing historical CSLI) . 16 See, e.g., United States v . Davis (Davis II) , 785 F.3d 498 , 511 ( 11th Cir . 2015 ), cert.
denied , 136 S. Ct . 479 ( 2015 ). 17 See id . 18 See, e.g., United States v . Graham (Graham I) , 796 F.3d 332 , 345 ( 4th Cir . 2015 ),
reh'g en banc granted , 624 F. App 'x 75 (4th Cir . 2015 ). 19 See infra notes 49-70 and accompanying text (discussing the rise of small cell 30 See infra notes 71-124 and accompanying text. 31 See infra notes 125-139 and accompanying text . 32 Alexis C. Madrigal , The 1947 Paper That First Described a Cell-Phone Network,
THE ATLANTIC (Sept. 16 , 2011 ), http://www.theatlantic.com/technology/archive/2011/09/the-
1947- paper-that-first-described-a-cell-phone- network/245222/. 33 Id. 34 Id. 35 Id . 36 See id.; see also JON AGAR, CONSTANT TOUCH: A GLOBAL HISTORY OF THE MOBILE
PHONE , 19 - 22 (2d ed. 2004 ), https://www.ucl.ac.uk/sts/staff/agar/documents/agar_constant
touch. 37 Thomas A. O'Malley , Using Historical Cell Site Analysis Evidence in Criminal
Trials , U.S. ATT'Y BULL 16 , 19 ( 2011 ), http://www.justice.gov/usao/eousa/foia_reading_
room/usab5906.pdf. 38 Id. at 27 . 47 WHAT 'S THE BIG IDEA ? , supra note 46, at 1. 48 Id. at 1-2. 49 Id. at 3. 50 Id. 51 Id . 52 WHAT'S THE BIG IDEA ? , supra note 46, at 1 . 53 Jeffrey G. Andrews et al., Femtocells: Past , Present, and Future, 30 ( 3 ) IEEE J. ON
SELECTED AREAS IN COMMUNICATIONS , 497 (Apr. 2012 ) ; WHAT'S THE BIG IDEA? , supra note
46, at 3. 54 WHAT 'S THE BIG IDEA ? , supra note 46, at 3 . 55 See, e.g., VERIZON, SAMSUNG NETWORK EXTENDER (SCS-2U01 ), http://www.verizon
wireless.com/accessories/samsung-network-extender-scs-2u01/ (last visited Jul . 23 , 2016 )
$ 249 .99); AT&T, AT&T MICROCELL, http://www.att.com/att/microcell/ (last visited Jul. 23 ,
2016 ) (advertising its femtocell as “a mini cellular tower, boosting cellular performance in
your home or small business”). 56 WHAT'S THE BIG IDEA? , supra note 46 , at 3; FUJITSU, HIGH-CAPACITY INDOOR
WIRELESS SOLUTIONS: PICOCELL OR FEMTOCELL ? 2 ( 2013 ) https://www.fujitsu.com/us/ 66 Martha DeGrasse, Verizon Explains Rollout of Small Cells, RCR WIRELESS NEWS
(July 29 , 2015 ), http://www.rcrwireless.com/20150729/network-infrastructure/verizon-
explains-small-cell-rollout-tag4 . One resident protested Verizon's proposed location for a
Boom , (Oct. 31 , 2015 ), http://sanfrancisco.cbslocal.com/ 2015 /10/31/san-francisco-residents-
battle-wireless-companies-cell-tower-building-boom-super-bowl-fifty/ . 67 Aaron Tilley, Los Angeles Becomes First City to Test the Future of Wireless
Connectivity with 'Small Cells' on Streetlights (Nov. 5 , 2015 ), http://www.forbes.com/sites/
aarontilley/ 2015 /11/05/los-angeles-becomes -first-city-to-test-the-future-of-wireless-
connectivity-with-small-cells-on-streetlights/#52196ae653ad. 68 In the Matter of Acceleration of Broadband Deployment by Improving Wireless
Facilities Siting Policies , 29 F. C.C. Rcd . 12865 , No. 16 ( 2014 ). 69 Id. at 12876 . 70 United States v. Carpenter, Nos. 14 - 1572 , 14 - 1805 , 2016 WL 1445183, at * 9 ( 6th Cir .
Apr. 13 , 2016 ) (describing the accuracy of GPS data); Stephanie K. Pell & Christopher
Access To Location Data That Congress Could Enact , 27 BERKELEY TECH. L.J. 117 , 132
( 2012 ). 71 U.S. CONST. amend. IV. 72 Id . 73 See Groh v. Ramirez , 540 U.S. 551 ( 2004 ). 74 United States v. Davis (Davis I) , 754 F.3d 1205 , 1212 - 13 ( 11th Cir . 2014 ), reh'g en
banc granted, opinion vacated, 573 F. App'x 925 (11th Cir . 2014 ) and on reh'g en banc in
part , 785 F.3d 498 ( 11th Cir . 2015 ) cert . denied, 136 S. Ct . 479 ( 2015 ) (discussing the two
theories of Fourth Amendment searches and their history) . 75 See United States v. Jones, 132 S. Ct 945 , 949 - 50 ( 2012 ). 76 See id . (citing Kyllo v . United States , 533 U.S. 27 , 31 ( 2001 )); Orin Kerr, The Fourth
Amendment and New Technologies: Constitutional Myths and the Case for Caution, 102
MICH. L. REV . 801 , 816 ( 2004 ) (“[O]ur Fourth Amendment jurisprudence was tied to
common-law trespass, at least until the latter half of the 20th century .”). 77 389 U.S. 347 ( 1967 ). 78 Id. at 353; see also Olmstead v. United States , 277 U.S. 438 , 464 ( 1928 ), overruled by
Katz , 389 U.S. at 353 . 79 Katz, 389 U.S. at 348 . 80 Id. 81 Id. at 347 . 82 Id. at 347 , 352 - 53 . 123 Id. 124 Id. at 2497 (Alito, J, concurring in part and concurring in the judgment ). 125 Wiretap Act , 18 U.S.C. § 2510 ( 2012 ); DANIEL J. SOLOVE ET AL., INFORMATION
PRIVACY LAW 264-65 (2d ed. 2006 ). 126 Electronic Communications Privacy Act of 1986 , Pub. L. No. 99 - 508 , 100 Stat. 1848
( 1986 ) (codified as amended at 18 U .S.C. § 2510 et seq.); Stored Communications Act, Pub.
L. No . 99 - 508 , 100 Stat. 1860 ( 1986 ) (codified as amended at 18 U .S.C. § 2701 et seq.);
SOLOVE ET AL., supra note 125 , at 265 . 127 See In re Elec. Commc'n Serv. to Disclose , 620 F.3d 304 , 314 ( 3d Cir . 2010 )
Communications Act , and a Legislator's Guide to Amending It, 72 GEO . WASH. L. REV.
1208 , 1219 ( 2004 ). 128 18 U.S.C. § 2703(c)(1)(A) ( 2016 ). 234 See infra notes 271-278 and accompanying text . 235 Davis II , 785 F.3d 498 , 515 ( 11th Cir . 2015 ), cert. denied, 136 S. Ct . 479 ( 2015 ). 236 See supra notes 49-70 and accompanying text (discussing the rise of small cell
technologies) . 237 See Brief for American Civil Liberties Union et al . as Amici Curiae Supporting
Defendants , United States v. Carpenter, Nos. 14 - 1572 , 14 - 1805 , 2016 WL 1445183 ( 6th
Cir . Apr. 13 , 2016 ), 14 - 20 . 238 See, e.g., DeGrasse, supra note 66 (describing Verizon's planned installation of 400
small cells on light poles and utility poles in San Francisco); Soder, supra note 61 (outlining
Tilley, supra note 67 (discussing the installation of SmartPoles in Los Angeles). 239 United States v. Karo , 468 U.S. 705 , 715 ( 1984 ).