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-- EveShabto - 05 Mar 2017


Cellular phones have become a staple of the modern American’s life. As of January 2017, 95% of American adults owned a cell phone, and 77% owned smartphones. The Supreme Court has noted that cell phones have become “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.” Cell phones are “simultaneously offices and personal diaries” because they contain “the most intimate details of our lives: financial records, confidential business documents, medical records and private emails.” Aside from the content stored in cell phones, phones also generate location data: Cell Site location information (“CSLI”).

CSLI Technology

CSLI allows cell service providers to track and store massive amount of information about a user’s physical movements. CSLI is generally divided into two categories: historical data and real-time data. Historical data is location data that has accumulated over time and is stored by the cell service provider, while real-time data is current data that can be used to determine the current location of the cell phone. Although courts have generally held that law enforcement must obtain a warrant before gaining access to real-time CSLI, many courts maintain that historical cell site data is not afforded the same protection. But a brief delay in the disclosure of the data should not significantly diminish an individual’s privacy interest in the data.

The Fourth Amendment and the Stored Communications Act

The Fourth Amendment guarantees “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures,” and that “no Warrants shall issue, but upon probable cause.” A government search within the meaning of the Fourth Amendment violates “a subjective expectation of privacy that society recognizes as reasonable.” However, law enforcement can obtain historical CSLI without obtaining a warrant but instead with a court order under the Stored Communications Act (“SCA”) because many jurisdictions consider CSLI “non-content” information, like the address on an envelope. Under the SCA, obtaining non-content information does not require probable cause; only “specific and articulable facts” and “reasonable grounds to believe” the information sought will be “relevant and material” to an investigation. This standard is hardly a standard at all. The original SCA was designed as a statutory stand-in for uncertain Fourth Amendment protection. However, as long as courts considered CSLI to be non-content information, the SCA is entirely inadequate. This paper argues that Courts should make clear that cell phone users have a reasonable expectation of privacy in their historical cell site location information and the Fourth Amendment applies.

Reasonable Expectation of Privacy in CSLI

In order for CSLI to possess Fourth Amendment protection, the traditional Katz two-prong test tells us that individuals must have (1) an actual, subjective expectation of privacy in their CSLI, and (2) society must be prepared to acknowledge that expectation as reasonable. Americans have a subjective expectation of privacy in the CSLI, and the Supreme Court has indicated that Americans have an objective expectation to be free from warrantless government surveillance.


The majority of Americans has no idea that cell phone service provides store their CSLI and regularly allow the government access to those stored records, without a showing probable cause. It is absurd for courts to decide that cell phone users assume the risk their CSLI will be shared if they are not aware that the information is being stored in the first place. Furthermore, the Americans who are aware that their CSLI is stored and shared with the government still consider CSLI to be sensitive information. In 2014, the Pew Research Center found that 82% of American adults considered data that showed the details of their physical location over time to be more sensitive information than the content of their text messages, relationship history, web browser history, and religious or political views.


The objective prong in Katz requires courts to “make a normative finding about whether users should be entitled to view the object of the search as private.” The question for courts to ask is whether under “under our system of government, as reflected in the Constitution, we should impose on our citizens the risk of the electronic listener or observer without at least the protection of a warrant requirement.” In United States v. Jones, five justices recognized the sensitive nature of location information. Although Jones involved gathering location data with a GPS device, Justice Alito in his concurrence, discussed that recent technological developments have led to a plethora of devices with tracking capabilities, and he explicitly singled out cell phones to be the most considerable. Alito expressed further concern that novel tracking devices will “continue to shape the average person’s expectations about the privacy of his or her daily movements,” suggesting that new surveillance methods will alter the Katz analysis to focus on normative considerations.

Justice Sotomayor, also concurring, expressed her concerns about protecting location information since even short-term GPS monitoring generates a precise, comprehensive record of a person’s public movements that reveal a lot about a person’s work, religion, sexual associations, etc. and can be stored and searched years into the future. Furthermore, Sotomayor stated 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” because “whatever the societal expectations, [those expectations] can attain constitutionally protected status only if our Fourth Amendment jurisprudence ceases to treat secrecy as a prerequisite for privacy.”

The Third Party Doctrine Should not Apply

Justice Sotomayor in Jones recognized that secrecy may not be a prerequisite for privacy: just because society may disclose certain information to a third party for limited purpose, does not mean that society does not also expect the information to remain private. CSLI is a prime example of this idea. First, cell phone users do not “voluntarily” share location information. Typically, a cell phone user’s only way to avoid CSLI tracking is to manually power off the mobile phone and remove the battery. In this sense, the user’s solution is essentially not to have a working phone at all. By virtue of having a cell phone powered on with the ability to auto-refresh apps, the user enables their service provider to track their location. Second, even if society accepts the idea that cell phones generate CSLI, this does not preclude society from expecting their service provider will not share this data with the government, absent probable cause.



1. Mobile Technology Fact Sheet, PEW RES. CENTER, http://www.pewinternet.org/fact-sheets/mobile-technology-fact-sheet/ (last visited Mar. 4, 2017)

2. Riley v. California, _ U.S. _, 134 S. Ct. 2473, 2484 (2014).

3. Lauren E. Babst, Note, No More Shortcuts: Protect Cell Site Location Data With a Warrant Requirement, 21 Mich. Telecomm. & Tech. L. Rev. 363 (2015)

4. Kyllo v. United States, 533 U.S. 27, 33 (2001).

5. Jennifer King & Chris Jay Hoofnagle, Research Report: A Supermajority of Californians Supports Limits on Law Enforcement Access to Cell Phone Location Information 8-9 (Apr. 18, 2008)(unpublished manuscript), available at http://ssrn.com/abstract=1137988.

6. Mary Madden, PEW RESEARCH CENTER, PUBLIC PERCEPTIONS OF PRIVACY AND SECURITY IN THE POST-SNOWDEN ERA, 36-37 (Nov. 2014), available at http://www.pewinternet.org/2014/11/12/public-privacy-perceptions/

7. United States v. Jones, 132 S. Ct. 945, 956 (2012) (Sotomayor, J., concurring) (expressing doubt that people “reasonably expect that their movements will be recorded and aggregated in a manner that enables the Government to ascertain... their political and religious beliefs, sexual habits, and so on.”).



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r3 - 06 Mar 2017 - 22:12:10 - EveShabto
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