grouchomarxist writes "According to this article at CNN: Police arrested a man they said tracked his ex-girlfriend's whereabouts by attaching a global positioning system to her car. Police said Gabrielyan attached a cellular phone to the woman's car on August 16 with a motion switch that turned on when the car moved, transmitting a signal each minute to a satellite. Information was then sent to a Web site that allowed Gabrielyan to monitor the woman's location." A ruling last year stated that police need a warrant to track individuals in a similar fashion.
http://slashdot.org/article.pl?sid=04/09/05/1730239