Real-Time Cell Phone Tracking Needs a Warrant: Fla. Supreme Court

In an age where it seems like surveillance just keeps getting more surveill-ey, the Florida Supreme Court has hit the brakes on the common police practice of using live cell phone location data to track a person's movements in real time.

Police had obtained a both a pen register and a trap-and-trace order to track the numbers Shawn Tracey was calling on his cell phone. A month later, the order had expired, but nevertheless, police accessed the real-time cell site location information of Tracey's cell phone without a valid order.

Real Time v. Historical Data

Ultimately, the question is whether real-time tracking of a suspect's physical location via cell phone is a Fourth Amendment search for which a warrant is required. The case law on this point is scant, and the only guidance from the U.S. Supreme Court comes from Justice Sonia Sotomayor's concurrence in Jones v. United States, where she worried about the government's ability to use a technology that "generates 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."

The Florida Supreme Court was similarly concerned, and dismissed the idea that real-time cell phone location was permissible as a voluntary disclosure to third parties: "While a person may voluntarily convey personal information to a business or other entity for personal purposes, such disclosure cannot reasonably be considered to be disclosure for all purposes to third parties not involved in that transaction."

Narrowing the Third-Party Disclosure Rule?

Such a statement is quite a change from the traditional third-party disclosure rule, which technology has threatened to vitiate. Every day, we surrender a multitude of information to private companies as we use our smartphones. Under the third-party disclosure doctrine, because we've given that information to someone else, there's no longer a reasonable expectation of privacy -- so why would police go to the trouble of getting a warrant when they could just ask the phone company for your whereabouts?

In 2011, Judge Alex Kozinski of the Ninth Circuit wrote a piece in the now-defunct publication The Daily expressing his concern that police would mine private databases for information: "Where police officers once needed a warrant to search your bookshelf for 'Atlas Shrugged,' they can now simply ask Amazon.com if you bought it. Where police needed probable cause before seizing your day planner, they can now piece together your whereabouts from your purchases, cellphone data and car's GPS."

But that was before Jones and well before the Florida Supreme Court's decision. The Florida court's decision is narrow, to be sure -- it applies to the location data accompanying 10 phone calls Tracey made -- but the reasoning has the potential to extend to all of the "voluntary information" that we're unknowingly transmitting when we're bopping around town with our phones to our ears.

Related Resources:

• Cops Need a Warrant to Grab Your Cell Tower Data, Florida Court Rules (Wired)
• New York Quickly Nixes Cellphone Tracking Devices in Phone Booths (The Intercept)
• Senator Al Franken Wants to Do Away With Stalking Apps (FindLaw's Technologist)
• Rise of 'Stingray' Cell-Phone Trackers Prompt FCC Probe (FindLaw's Technologist)