In a strong affirmation of the privacy interests of cellphone users, the Massachusetts Supreme Judicial Court (SJC) ruled unanimously earlier this week that law enforcement agencies in the Commonwealth must obtain a warrant to access anything more than a minimal amount of the cell-site location information (CSLI) that telecommunications companies collect about their users. The Cyberlaw Clinic filed an amicus brief in Commonwealth v. Estabrook on behalf of the American Civil Liberties Union of Massachusetts (ACLUM) and the Electronic Frontier Foundation (EFF) in support of privacy protection for CSLI.
As explained in a previous blog post on this case:
Cellular service providers must know where their subscribers are at any given time to provide them with service. Providers therefore collect vast quantities of location information, tracking the movements of customers wherever they go. Last year, in Augustine, 467 Mass. 230 (2014), the Supreme Judicial Court ruled that, in general, the police must get a search warrant to obtain location information from a cellular service provider. The ruling left open the possibility, however, that the police might be able to obtain a “brief period” of “six hours or less” of location information without a warrant but, instead, with a court order that is considerably easier to obtain.
At issue in Estabrook was whether law enforcement could obtain two weeks of CSLI with a mere court order, and yet take advantage of the Augustine exception, since it would only use six hours of this data in prosecuting the defendant. In rejecting this proposition, the SJC agreed with the position advocated by amici that the government cannot remedy the constitutional violation caused by conducting an unlawful, warrantless search by promising after the fact to use only what it might have lawfully obtained under the “six-hour” exception.
Although the SJC did not adopt the blanket warrant requirement for CSLI urged by amici, it did significantly limit the scope of the “six-hour” exception by clarifying that it applies only to “telephone call CSLI.” This form of CSLI is generated only when a user makes or answers a voice call, in contrast to the “registration CSLI” that records the location of a powered cellphone every seven seconds and can now only be obtained pursuant to a warrant.
This result leaves open some questions. To be sure, “[r]egistration CSLI obviously generates a more complete and revealing picture of users’ movements than call CSLI,” notes Andrew Crocker of the EEF, “[b]ut that’s hardly enough to serve as the basis for a constitutional rule.” “Why,” he asks, “should you have more protection when you walk around playing Words with Friends than when you actually exchange some words with a friend over the phone?”
Even so, “[t]he Supreme Judicial Court’s decision in Commonwealth v. Estabrook confirms Massachusetts’ role as a leader in protecting our location information from unreasonable government intrusion” said Jessie Rossman, a Staff Attorney with the ACLU of Massachusetts. “Reaffirming Augustine, today’s holding is a victory for individuals throughout the Commonwealth and their reasonable expectations of privacy in their location information,” she added.
HLS Cyberlaw Clinic students Abigail Colella (’16), Sandra Hanian (’15), and Travis West (’16) worked closely with Vivek Krishnamurthy and Andy Sellars of the Clinic, along with the amici, to prepare and file the brief.