I read an article somewhere that said the car thieves have a new scam that they're using: they'll claim that they lost their keys to their car, and can get a duplicate set made if they provide the VIN number to the car dealership - which they can obtain from peeking through the car's windshield that they plan to steal, which is right on the dashboard in plain sight of the car on that little metal plate!
You're supposed to cover the metal plate w/ a piece of tape, so they can't see it. But what if you lose your own keys? Then what are YOU supposed to do??
The crooks always find a way, no matter what you do..