Face it, night time is the perfect time for stealing a car. Everyone else is sleeping, the roads are quiet and no one can see a thief jimmying the car window or hot wiring the ignition. And really, who’s to know if the driver is a car thief or simply a guy tossed out of bed by his pregnant wife for a pint of Cherry Garcia from the local 7-11? Unless the driver is driving erratically, then there’s no reason to be suspicious. Or is there?

The C.A.T. sticker that you’ve got plastered to your windshield is reason enough to be suspicious, if your car is being driven during the middle of the night. C.A.T. is an acronym for Combat Auto Theft, a federally funded program that provides the legal car owner with a highly visible window decal that identifies your car as registered in the C.A.T. program.

Across the country, many jurisdictions have enacted C.A.T. or Watch Your Car programs to aid in car theft prevention. There are usually no fees involved, since the programs are funded with insurance surcharges or car registration fees. Statistics have proven that the programs work; for example, in New York City, cars registered under C.A.T. have a theft rate of less than 1%, while non-registered cars have a theft rate of more than 7%.

How it works is this: If your car is being used during specific night time hours (which can vary according to the jurisdiction you are registered in), the police have the right to stop the driver of the car and demand proof of ownership. If that happens to you, you better be prepared to show your car’s registration and driver’s license. And a picture from your wife’s last sonogram couldn’t hurt, either.