As a matter of fact, most car thieves are dick-licking, ball-sucking, cock-tingling farkers with little brain matter to go and steal/damage people's pride and joy - yes, you are right. However, there are so many ways to disarm even the most sophisticated alarm. When I got my Viper alarmed installed on my GTR a few weeks ago, I had a good chat with one of the installers about car theft etc, and he said most alarms can be disabled quite easily if the crook knows the basics. Shiit, he even said that most thieves nowadays will just tow your car away, take it home to their garage, disabled the alarm with descent tools and then will strip the fark out of it before driving it to a driver, park or street and just dumping it there. Why risk driving it to be spotted? And let's face it, if you see a car on a tow truck, I don't think you'd look twice and wonder if it's stolen.
However, I agree with you mate...better make it harder for those faggots then not.