I'm always amazed at how many games at shows are only marginally playable (and look like they haven't seen so much as a good waxing, much less new set of rubbers, in god knows how long). That said, it is true that being wailed on for 10 hours straight at a show will put a hurt on any parts that may have been marginal but not crying out for replacement when the game was being played at home. Several years ago, I remember a Tommy at Allentown which was playing like-new on Friday afternoon, but the flippers were crapping out by noon on Saturday.

I baby my games and try to keep them playing as perfectly as I can. Personally, I choose not to bring them to shows, as the admission fee is worth more to me than the time and money I'd need to invest in bringing the game back to peak performance afterward.

Eventually I figured out that, for me, playing a whole lot of pinball isn't my primary reason for attending shows. I like to see what new games are there, see what cool deals I might be able to get, maybe run into other pinheads, and if I'm lucky there'll be a few games I like that are playing decently. Also a good chance to get a good look at a game you are considering and/or line up a sale or trade.

I don't know about anyone else, but I'd be down with the idea that you bring a problem game to a show and arrange to work on it there, that seems like a great way to take advantage of all the expertise available in one spot!