Very few stereo thieves write down the vehicle VIN on the deck as they're running away. No point in making it even easier for the police to figure out its stolen property, and they're usually in a bit of a hurry. Assuming they have a sharpie marker in one hand instead of a screwdriver or window smasher. Assuming they can read and write.

One interesting problem "security" guys have is overcomplicating plots. Your average meth head is waaay too zonked out of his mind to memorize which VIN goes with which radio, or even which OEM radios need a code.

Another problem is via the VIN they know instantly that your car is a '98. Well my cheapo commuter car is also a '98, and its approximately worthless at this point. Anyone stealing my worn out, partially broken, approx 2002 model year aftermarket deck pretty much deserves the pain they're about to experience. At a flea market I might be able to give it away... That may very well be Honda's point of view. Now try that again with a new 2013 $2000 GPS DVD player deck and they might hassle you.