I think a lot of people try to show off, "look how good at pinball I am" by shaking, nudging and hitting way beyond what's needed for normal play. From what I observed, a lot of people also forget how much work it is to fix up, bring a game to the show and keep it working the entire time . Hell, I brought my Bacardi Cuba Libre and it STILL managed to break (ball tray fell out somehow, people stole at least 4 balls from it). And thats just a game with no flippers and no electricity needed!
I think most expect their games to need routine maintenance after the show, or even a minor repair since the rough-player concentration is probably a lot higher at these shows than normal location play, but there's always a limit. Some people don't treat other people's property with respect -- pinball or not, and no amount of awareness will change that.
What didn't help is the "Free Play Rules" banner at Pintastic. It's wayyyy too long and nobody's going to take the time to read it. It needs just a few, bold bullet points with the ground rules and consequences for rough play listed.
As far as crop dusting goes, I don't think I've ever smelled more lingering, sausage-y burps, nasty potato chip farts or wet dog smells in my life. Next year I'm bringing a gas mask.
-Doug