There is more than one way into your car alot of cars you can get into without damaging anything if you know what you are doing. Some cars on the market are unbelivably easy to get into like old vauxhalls and fords. My car if you kick it hard in the right place thinks it has been in a crash and opens the central looking. Another make the older vechile you get a tennis ball cut a hole in it 1 inch round place it over the lock give it a good hit and it fools the sensor in the pnuematic central locking and it starts the vacum pump and all the doors unlock.

The other factor is the idiot factor your car thief is going to see cables but won't notice any lack of damage etc but will move on they are opertunists they ain't going to investigate a car with a sign of the stereo already missing