You call 911, give them your information, and they turn on a radio receiver to let any passing cop that is properly equipped nab the thief. According to advertising, over 90% of the time the car is recovered (as opposed to 68% without), a quarter of the time an arrest is made, and on average 1/5 of the damage is done.

Just trying to figure out whether my odds of being stolen make it worthwhile. The Googling that I'm doing suggest that it may well be. :-(

Cheers,
Ben