I am a little surprised at all of the shows that seem to let new cars in. Our big show here, Kool April Nights won't let any car newer than a 1979 in and many of the smaller shows are the same. A couple of the really small ones will let any car in as they don't get many, and one of them has quit having a car show every year.
I haven't see any of the reaching under the finder stuff, but some of the people here who take their cars to shows before they are completely finished would end that. All it would take is to get one of those rough fiberglass splinters stuck in your finger and I doubt if they would want that again.
Ron