Police can no longer use cell phone towers to track criminal suspects without a warrant. Image: Shutterstock
The government and police regularly use location data pulled off of cell phone towers to put criminals at the scenes of crimes—often without a warrant. Well, an appeals court ruled today that the practice is unconstitutional, in one of the strongest judicial defenses of technology privacy rights we've seen in a while.
The United States Court of Appeals for the Eleventh Circuit ruled that the government illegally obtained and used Quartavious Davis's cell phone location data to help convict him in a string of armed robberies in Miami and unequivocally stated that cell phone location information is protected by the Fourth Amendment.
"In short, we hold that cell site location information is within the subscriber’s reasonable expectation of privacy," the court ruled in an opinion written by Judge David Sentelle. "The obtaining of that data without a warrant is a Fourth Amendment violation."
In Davis's case, police used his cell phone's call history against him to put him at the scene of several armed robberies. They obtained a court order—which does not require the government to show probable cause—not a warrant, to do so. From now on, that'll be illegal. The decision applies only in the Eleventh Circuit, but sets a strong precedent for future cases.
The American Civil Liberties Union, who argued the case, said that the decision is a "resounding defense of the Fourth Amendment's continuing vitality in the digital age."
"This opinion puts police on notice that when they want to enlist people’s cell phones as tracking devices, they must get a warrant from a judge based on probable cause. The court soundly repudiates the government’s argument that by merely using cell a phone, people somehow surrender their privacy rights," Freed Wessler, who argued the case, said in a statement.
"The United States further argues that cell site location information is less protected than GPS data because it is less precise. We are not sure why this should be significant."
Indeed, the decision alone is a huge privacy win, but Sentelle's strong language supporting cell phone users' privacy rights is perhaps the most important part of the opinion. Sentelle pushed back against several of the federal government's arguments, including one that suggested that, because cell phone location data based on a caller's closest cell tower isn't precise, it should be readily collectable.
"The United States further argues that cell site location information is less protected than GPS data because it is less precise. We are not sure why this should be significant. We do not doubt that there may be a difference in precision, but that is not to say that the difference in precision has constitutional significance," Sentelle wrote. "That information obtained by an invasion of privacy may not be entirely precise does not change the calculus as to whether obtaining it was in fact an invasion of privacy."
The court also cited the infamous US v. Jones Supreme Court decision that held that attaching a GPS to a suspect's car is a "search" under the Fourth Amendment. Sentelle suggested a cell phone user has an even greater expectation of location privacy with his or her cell phone use than a driver does with his or her car. A car, Sentelle wrote, isn't always with a person, while a cell phone, these days, usually is.
"One’s cell phone, unlike an automobile, can accompany its owner anywhere. Thus, the exposure of the cell site location information can convert what would otherwise be a private event into a public one," he wrote. "In that sense, cell site data is more like communications data than it is like GPS information. That is, it is private in nature rather than being public data that warrants privacy protection only when its collection creates a sufficient mosaic to expose that which would otherwise be private."
Finally, the government argued that, because Davis made outgoing calls, he "voluntarily" gave up his location data. Sentelle rejected that, too, citing a prior decision by a Third Circuit Court.
"The Third Circuit went on to observe that 'a cell phone customer has not ‘voluntarily’ shared his location information with a cellular provider in any meaningful way.' That circuit further noted that 'it is unlikely that cell phone customers are aware that their cell phone providers collect and store historical location information,'” Sentelle wrote.
"Therefore, as the Third Circuit concluded, 'when a cell phone user makes a call, the only information that is voluntarily and knowingly conveyed to the phone company is the number that is dialed, and there is no indication to the user that making that call will also locate the caller,'" he continued.
Unfortunately for Davis, the court also held that the government had enough evidence to convict him anyway, and did not completely overturn his 162-year sentence.