[xeon]

Another little issue with this is a lot of car keys are chipped today. It is possible to program a new key to the car yourself... but sometimes you need a key already "authenticated" to use in the process and you have to know the process. But if you did get a key, a thief could certainly enter the car which isn't so hot.

Looked it up in urban legends and some interesting stuff came up:

While there has been at least one well-publicized case (in 2002) of an auto theft ring using a ploy similar to the above to steal vehicles from used car lots, it is a complicated and time-consuming modus operandi and not the most likely way a thief might try to steal your car.

Still, the method can work, as proven in an experiment conducted by WTAE-TV News in Pittsburgh:

After getting permission from the owners, we jotted down VIN numbers from four different vehicles. Then, we went to four diffrerent car dealerships with a hidden camera. We told the same kind of story that a thief might tell: we locked the key in the car and needed a new one.

First, we went to a dealership and tried to get a key made for a 2003 Blazer. It couldn't have been any easier.

Next, we walked into another dealership with a phony story. Half an hour later, we had a key that got us into -- and away with -- the car. The key cost $2 and we paid cash. No one asked for identification.

Three out of the four car dealers struck duplicate keys with no questions asked, the reporters found, even though most dealerships have a policy of demanding identification before doing so. A different investigation conducted by the Sacramento Bee in 2003 found that car dealers were not only aware of the scam but in some cases believed they had actually foiled attempts to illegally obtain keys by insisting on proper documentation from the perpetrators.

Covering the dashboard VIN # is an option for vehicle owners concerned that they may be victimized in this manner, but, since some states prohibit it, checking local laws is advisable first.