"[T]he Supreme Court has recognized that a Fourth Amendment search may occur through the use of advanced technology to reveal detailed and personal information about individuals," the groups' amicus brief states. "These characteristics apply to GPS tracking, and a warrant should therefore be required for its unconsented use. Such a ruling also comports with the public's rejection of 'Big Brother' police surveillance, and with the empirical evidence that Americans have a strong expectation of privacy that their every movement by automobile or foot will not remotely be tracked or recorded by private parties or law enforcement."
The case in question involves Lawrence Maynard and Antoine Jones, who were alleged to have distributed and sold cocaine in Washington, D.C.; Maryland; and elsewhere from 2003 through 2005. In the course of investigating the pair, police used surveillance, informants, and a GPS tracking device hidden in Jones' vehicle.
According to court documents, the investigation concluded with the arrest of the defendants and the seizure of 97 kilograms of cocaine, 549 grams of crack cocaine, and more than $850,000 in cash.
The principle at stake here is whether law enforcement agencies can track people without first obtaining a warrant from a judge. The EFF and the ACLU note that the courts have placed limits on the use of technology to obtain information. For example, thermal imaging of a person's home without a warrant has been disallowed.
The groups also argue that GPS tracking could undermine the First Amendment right to associate privately with others by allowing the government to identify a person's associates through their location.
"GPS tracking can reveal whether a person visits a Planned Parenthood clinic, patronizes a gay bar, or attends a meeting of an unpopular political organization," the brief states.
The filing argues that GPS devices are growing more powerful, with versions that work indoors, and more versatile, in the form of tracking darts that can be shot at fleeing vehicles.
"In sum, warrantless, remote GPS tracking trespasses on individuals' reasonable expectation not to be tracked electronically, twenty-four hours a day, for extensive periods of time," the brief concludes.
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