Cyber Law Archives | PLDO Law Blog

Is your cell phone nearby? Are you reading this article on it right now? It’s probably no surprise to you that Americans are with their cell phones constantly. And, you may already know that your cell phone is constantly scanning for the best signal. What you may not know is that in the process, your cell phone connects to cell sites and generates a time-stamped record of that connection: cell-site location information (CSLI). That CSLI tells a story about all of your comings and goings, tracing back up to five years. In a landmark decision issued this term, Carpenter v. United States, No. 16-402 (June 22, 2018), the Supreme Court held that the government’s access of CSLI was a search under the Fourth Amendment and, therefore, required a warrant.

Carpenter involved a criminal defendant whose movements over approximately three months were captured by CSLI held by two cell phone service providers. The government obtained that data from the providers (without a warrant) and used it to help convict the defendant of robbery, pointing out that he was physically close to four of the robberies while they were taking place, and relying on his CSLI to do so.

In the past, the Supreme Court has held that there is no reasonable expectation of privacy in information voluntarily shared with third parties. That’s common sense—if one posts a yard sign saying “I robbed the bank,” I don’t have a reasonable expectation that the information would stay private. Likewise, it wouldn’t be a “search” if a police officer stood outside one’s house and read the sign.

But the Supreme Court concluded that CSLI is different. Not only are cell phones “indispensable to participation in modern society,” the Court said, apart from disconnecting one’s phone entirely, there is no way to avoid leaving behind the trail of location data. Could anyone really be said to voluntarily assume the risk of turning over what the Court called a “comprehensive dossier” of one’s physical movements? The Carpenter majority didn’t think so. Peering into the vast trove of location data stored by cell phone providers constituted a “search” in the Court’s eyes, and a warrant would be needed as a consequence. That’s a relief for the millions of Americans who—as the Court cheekily observed in another case—see their cell phone as “a feature of human anatomy.”

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This term, the U.S. Supreme Court will decide whether the police can track the real-time cellphone-based location and movements of a suspect using the suspect’s cellphone records. In Carpenter v. U.S., the police obtained Mr. Carpenter’s cellphone number from one of his alleged accomplices. Using this cellphone number, the police were able to obtain Mr. Carpenter’s “transactional records,” which permitted the police to piece together 12,898 pieces of data from the cell towers that allegedly showed Mr. Carpenter’s movements over a period of four months.

The Supreme Court’s decision in this case could have far-reaching consequences, especially as more and more automobiles contain real-time GPS location data and self-driving cars come onto our roadways. This case poses serious questions that courts must struggle with: do drivers or cellphone users have a reasonable expectation of privacy in their movements, or is this data fair game for police or other government entities? Are consumers even aware of or know about the vast amounts of data being gathered about them in the background of their apps, devices, and cars? Would consumers behave differently – or make different product choices – if they knew that someday the police could retrace their movements simply based upon the data stored on their phone or in their cars?

These are real and complex questions posed by this case, and it will be interesting to see how the Supreme Court decides the issue. If the Court decides in favor of the government, it could reinvigorate the privacy debate we recently saw with Mark Zuckerberg’s testimony. But, for now, it seems that the tension between technology and privacy is as stark as ever. Only time will tell how and whether courts will strike a balance between legitimate police interests and the privacy rights of those of us who don’t pay much attention to the staggering amounts of digital bread crumbs we leave behind.