Most people that attend pinball shows are respectful of your games. Of course, there will always be a small minority of people that just don't care and they will find some way to damage your game. I brought multiple games to a number of shows from 1999-2014, one year trucking 18 games alone. I can count on one hand the amount of damage that was done through abuse, some damage that was unintentional like a guy rolling his game on a cart right into the side of my Indy 500 at Pinball Expo in 2003, left a big scuff on the head. He was sorry about it, just moving his game too fast and couldn't make the turn, ha! Worst year was at Pinball Expo in 2006, with a few issues that were clearly abuse. Didn't stop me though, still brought games after that. Probably more risk from just moving the games back and forth to and from the show. Only reason I stopped bringing games is because it is too damn much work to bring a truckload of games.
Games on location these days seem to take more abuse than ever. Those that say the games are built to take it haven't seen a playfield knocked off its supports and sitting cockeyed in the cabinet, or legs bent from game sliding, or plungers bent from whatever, flipper buttons smashed from rings, necks cracked on older games from someone picking up and slamming the game up against the wall, dents in coin doors from a knee or kick. All this stuff can be fixed, just don't kid yourself thinking that games can always take rough treatment because sometimes they break.