Now, law enforcement can walk onto your driveway, place a GPS tracking device on your car, without your consent, and without a warrant, and use that information as evidence in a criminal trial.
While this helped law enforcement nab a drug dealer, proving the usefulness of the tactic, it undermines not only any expectation of privacy, but also any oversight of the methods that law enforcement uses. Obtaining a warrant for any search or seizure on private property is an important check in the powers that law enforcement can utilize. Not having to obtain a warrant beforehand means that any police department could place a GPS device on any car for any reason.
Advocates argue that it is no different than having a suspect under surveillance, being followed by actual officers.
But supporters of the decision see the GPS trackers as a law enforcement tool that is no more intrusive than other means of surveillance, such as visually following a person, that do not require a court's approval.
"You left place A, at this time, you went to place B, you took this street -- that information can be gleaned in a variety of ways," said David Rivkin, a former Justice Department attorney. "It can be old surveillance, by tailing you unbeknownst to you; it could be a GPS."
He says that a person cannot automatically expect privacy just because something is on private property.
"You have to take measures -- to build a fence, to put the car in the garage" or post a no-trespassing sign, he said. "If you don't do that, you're not going to get the privacy."
This analogy falls apart when pushed to its logical conclusions.
Should police be able to put a device on your car that tracks your car's speed? Then, whenever you went over the speed limit, they could just send you a ticket in the mail. Following the analogy, it wouldn't be any different than a police officer catching you on the highway with a radar gun.
Yet...intuitively that doesn't feel right, does it?
The main issue involves police officers being able to go onto private property to install a surveillance device. I suppose that could be gotten around by waiting for the suspect to go to the grocery store and putting the device on there, but then you still have some expectation of privacy with your vehicle. Law enforcement is not allowed to pull you over and search your car without probable cause, which a suspect probably wouldn't provide if he's just going to the grocery store.
Another issue might concern the actual GPS device. Suppose you find one on your car and you take it off and destroy it. Are you going to be held liable for destroying "evidence" or destroying equipment used by law enforcement? If you find it and don't destroy it, do you have the right to demand that it be removed?
We don't want to go down this path.