The Florida Supreme Court has ruled that warrantless tracking of people's location using their cell phone signal is unconstitutional, a move that could have far-reaching consequences and suggests that the most common use of police surveillance tools called StingRays is illegal.
The StingRay, if you aren't familiar, is essentially a fake cell phone tower that is used by at least 45 branches of law enforcement in the United States to track criminal suspects (the UK uses them as well). But the way it works—as a cell tower spoofer—means that, by design, all cell phones within a certain geographical area will connect to it, meaning police are sweeping up location information about everyone nearby.
It's a great decision, and it's a big deal
When police have access to StingRays, they use them often: In 2011, the Los Angeles Police Department used it for 340 different investigations; in Tallahassee, Fla., police used them for 250 investigations between 2007 and 2014. Most often, tracking of specific suspects is done without a warrant.
StingRays aren't at the heart of Thursday's Florida Supreme Court Decision; warrantless cell phone location tracking is, according to court justice Jorge Labarga's opinion. Nonetheless, the most common use of StingRays would fall under his decision.
A map of known StingRay use in the US. Image: ACLU
In this instance, a suspected cocaine dealer, Shawn Tracey, was tracked in 2007 by police without a warrant. Labarga said this was a violation of the Fourth Amendment.
"Regardless of Tracey's location on public roads, the use of his cell site location information emanating from his cell phone in order to track him in real time was a search within the purview of the Fourth Amendment for which probable cause was required," Labarga wrote.
No matter where you are, you're giving your location data to third parties: Facebook, Google, all manner of apps you've opted into. But that doesn't give police or the government in general permission to scrape that data or con you into giving it to them, he suggested.
Even if they're tracking a specific suspect, they're getting info about every bystander
"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," he wrote.
"Requiring a cell phone user to turn off the cell phone just to assure privacy from governmental intrusion that can reveal a detailed and intimate picture of the user's life places an unreasonable burden on the user to forego necessary use of his cell phone, a device now considered essential by much of the populace," he continued.
Again, this decision only counts in Florida for the time being, but it's the first time a high court has ruled, based on the US Constitution, that the practice is illegal, and it sets a strong precedent for future cases. Previously, New Jersey and Massachusetts made similar rulings using their state constitutions.
"It's a great decision, and it's a big deal," Nate Wessler, a staff attorney with the American Civil Liberties Union, told me. "The way the court's decision is written, it would apply to most StingRay use."
Wessler said that while this is a huge decision, it's not clear yet if all StingRay use—warrant or not—may one day be ruled unconstitutional. The ruling simply hasn't been tested yet.
"It's an unanswered question, but the devices wrap up innocent people, which looks like a dragnet search that's not legal under the Fourth Amendment," he said. "Even if they're tracking a specific suspect, they're getting info about every bystander. That's a concern."