The harder it is to steal the car the more likely it is you'll get injured or killed by the people trying to take it.

The scum doesn't give a shit about you, and when they can earn thousands by taking it, the rewards for a few minutes work is to tempting. In their eyes it's your fault if you get hurt, you should have just handed it over.Kill them and if you are not thrown in jail, you'll be targeted by the scums family as their mentality is 'my little angel didn't deserve to be killed'.

Sadly the best you can really do is make yourself and property less of a target so that they will move on and choose an easier target.

Cars will get taken, and although it wont stop it, companies making it easier to trace the car and get the car back and the law giving out stronger punishment will only help to make it less of an easy source of cash.