car people i know have respect for other peoples cars, they will ask before leaning on your car but never put stuff on it. no smoking/eating in cars, drinking is but only if approved by driver, no yelling or signs (just makes you look dumb anyways.)
Its the NON car enthusiasts that are my problem, fingers/HANDS on windows, keys on roof... i go off and especially when my cars back from the shop with a new spray anyone who comes near it with food/keys etc is getting a kick in the face.
At least i have paint scratch and dent insurance on all vertical panels...