The state attorney general of Maryland is taking an alarmingly aggressive stance on the use of controversial cell phone trackers known as cell site simulators, or StingRays, arguing in court that a suspect volunteered to be tracked simply by leaving his phone on.
In a brief filed earlier this week, Maryland attorney general Brian E. Frosh challenged a Baltimore court's decision in the case of Kerron Andrews, who was targeted by a cell site simulator, the once-secret surveillance device used by police and federal agents to track phones en-masse by impersonating cellphone towers, often without warrants.
Andrews, who faces multiple counts of attempted murder, had asked the court to dismiss the charges, citing Fourth Amendment concerns over the use of the surveillance device.
But the state argued that because cell phones constantly reveal their locations to carriers by pinging nearby cell towers, Andrews "voluntarily shared this information with third parties," including the police, merely by keeping his phone on.
In other words, if you don't shut off your phone, you're asking to be tracked.
"While cell phones are ubiquitous, they all come with 'off' switches," the state responded in the brief. "Because Andrews chose to keep his cell phone on, he was voluntarily sharing the location of his cell phone with third parties."
The argument is a terrifying but not unprecedented escalation of previous rulings regarding cell phone location privacy. In the past, courts—usually relying on legal precedents established well before cell phones existed—have held that no one has a reasonable expectation of privacy when data is "given" to third parties, even if that data is sent unwittingly or as part of the normal functioning of a device or service.
In other words, if you don't shut off your phone, you're asking to be tracked
"The government has indeed repeatedly argued that there is no [reasonable expectation of privacy] in cell phone location information, in court and out," Nathan Wessler, a staff attorney with the ACLU's speech, privacy and technology project, told Motherboard in an email. "In cases involving historical cell site location information, the government has danced around this argument, arguing that phone users give up their expectation of privacy in their location information merely by making and receiving calls."
Now the state of Maryland is saying that simply having a cell phone switched on is enough to nullify that protection, something which police, prosecutors and courts have hinted at before.
"Andrews … was quite aware that he was bringing his own cell phone into the house. And he was quite capable of turning it off," the state wrote. "The issue is whether Andrews can claim an objectively reasonable expectation of privacy in information which he was voluntarily broadcasting to third parties at all times."
One flaw in this argument is that it's possible to track phones even when they appear to be off. Malware reportedly used by the FBI and NSA can put a device into a low-power state when it's switched off, allowing it to continue reporting its location to nearby towers. And since most phones no longer have removable batteries, there's no way to be certain you're not being tracked unless you invest in a good quality Faraday pouch.
It isn't the first time a court has heard this kind of argument. In a 2013 DEA case, a New York magistrate judge said that "given the ubiquity and celebrity of geolocation technologies, an individual has no legitimate expectation of privacy in the prospective location of a cellular telephone where that individual has failed to protect his privacy by taking the simple expedient of powering it off."
The judge went on to claim that "the newsworthiness of cell phone tracking as a concept has waned, confirming that geolocation has moved from the unfamiliar to the commonplace."
Conversely, the Florida Supreme Court ruled in 2014 that "requiring a cell phone user to turn off their cell phone … 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."
"In the government's view, the only way to protect ourselves against warrantless tracking of our locations is to turn our cell phones into inert paperweights," Wessler, the ACLU attorney, told Motherboard. "But this would come at a significant cost, as having a functioning cell phone has become necessary to full participation in the civic, social, and economic life of the nation."
He continued: "Because Stingrays force phones to transmit information to the government that they would not otherwise transmit to the government, gather information about countless innocent bystanders, and probe the interiors of homes and other private spaces, a warrant is required."