A little more info:
http://www.snopes.com/crime/warnings/vin.asp
It really depends on the dealership. My mom's car has a key with a chip in it. The dealership she uses wouldn't even duplicate the original she had in her hand until she produced the registration, and they verified the info against the car and existing key.
It doesn't mean it couldn't happen, it did in "Gone in 60 Seconds" by paying off the guy behind the counter. But it is more difficult than that article leads you to believe. I would think any reputable dealer would check.
Bob
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