I understand your thoughts, but remember there are a lot of spectators at the car shows that know not to touch and to respect the car and the owner. I go to every car show in my area and have never touched a car and really enjoy looking at all the different rides and talking with people.
Since my car isn't finished yet, I am a spectator.
I get it though, for some reason people always want to touch the cars and that I don't understand! When I get my car done, I may just have to tie some ropes around my car to keep people away.