For what it's worth...
This is from personal experience. Took my 65 to school (where under 500 students attend) and parked it away from everyone else. Got out and found the car vandalized, school didn't do crap to find out who it was (happened in 2010). If you take it anywhere make sure it is well in your line of sight. If you are in a building check on it often to make sure no one is messing with it. There are an ungodly amount of envious assholes out there. Believe me when I say they come to car shows too, also be wary of small children. Basically anyone who you don't trust (and some you trust) could harm your car. In other words treat it like your child.
Proud owner of:
1965 Chevrolet Impala SS pure original 327 300hp,360ftlbs Muncie 21 4spd, 12 bolt rear, mist blue white interior, 17in cragar thrust wheels, super 44 flow master mufflers. status: 98% restored
2008 Roush 427R #528 All stock except Roush billet grille, Roush CAI 460hp, 425ftlbs, 5spd vista blue white graphics black leather with blue inserts, stock Roush wheels and exhaust. Status: waiting for many many upgrades
70 Dodge Challenger T/A 340 Six Pack 290hp factory rated (bull****) 4spd hemi Orange black interior rallye wheels, T/A exhaust. status: restoration in progress
75 MGB convertible 1.8L 90hp, of pure evil, 4spd Mars red (VW color) black top black interior wire wheels. Status: restored and for sale
Hunting for a black 03 terminator 10th anniversary coupe