I don’t think I can elaborate more on the story at CNN about the GPS device thief caught by GPS other than to quote:
“He apparently didn’t know what he had because he would be awfully stupid to steal a tracking device”
There's a story in my country, that a man had an affair with another woman in a family vehicle equipped with GPS anti-theft tracking systems. Apparently, motion sensors in the vehicle (while they were doing you know what..) set off the silent system, and sent a "your stolen car is now located at X" message to his wife's cell phone. Of course, they were caught!