My '87 Camaro Z28 was stolen out of a Southfield parking garage in the middle of the day.
They found it months later, stripped down to the engine block and the frame, on a street in Detroit.
The advice I was given at the time by one of the Southfield police officers was to stop carrying my registration and insurance information with the car. If the thief gets pulled over without them, odds are that he'll get stopped when the plates are run. Otherwise, he can just say he's borrowing the car from a friend.