Can cops attach a global positioning system (GPS) device to your car and use the information they gather to charge you with a crime? As long as they get a warrant first, courts across the country are ruling in their favor.

A Wisconsin appeals court last week said (pdf) it was fine for cops to use a GPS device to collect evidence against a man stalking an ex-girlfriend, because the police had a court-issued warrant, the Daily Kenoshan in Wisconsin reports.

The Wisconsin Court of Appeals concluded that, since neither a search nor a seizure occurs when law enforcement officers use a GPS device to track a vehicle while it is visible to the general public and that the technology simply made it easier for the police to do their job. In fact, the court subsequently issued a search warrant for the suspect's apartment based on information gathered using the GPS.

On the other hand, a New York appeals court this week granted a man convicted of robbing a Kmart in 2005 the right to a new trial because police had attached a GPS device to his van while investigating him for the crime without first getting a warrant to do so. The Times Union of Albany, N.Y., reports police tracked the man's van for two months, even replacing a battery that had worn out.

The court ruled police needed a warrant and to show probable cause. In the majority opinion, the court's chief justice wrote that the popularity and utility of GPS technology don't mean that it can be used in "a massive, undifferentiated concession of personal privacy to agents of the state," according to the Times Union. Dissenters on the court argued that police don't need a warrant to follow, photograph or videotape a suspect, so they shouldn't need one to use a GPS either.

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