The only thing I've had so far is finger prints. I sit in restaurants where I can watch people look at the car. About one third of the lookers who get close have to touch it. I get hand prints on the windows where people try to look through the window tint and various smears and prints on everything else. I've even seen 'responsible looking' old men who are as bad as children with the finger prints. Parking in conspicuous spots probably doesn't help the finger print problem. But I would rather have that than give people enough privacy to have their way with my car. I would advise against the electro-shock alarms unless you want toe prints on the car, too. :)