Quoted from rmarket:

That was a nice TAF that you brought. Thanks for bringing it.
I've taking games to almost every Allentown show (missed the first year and one year the game I was going to bring I got offered crazy money to sell it before it made it to the show) and every York show. I've been bringing at least 8 to the York Show the past few years. I understand all too well how much work and risk is involved with bringing a game to a show. Three of mine developed serious problems this year. We do watch closely for abusive patrons. It is one of the few things that you will get instantly kicked out of the show for without any warnings.
We've floated an idea similar to yours and the response was underwhelming. One issue is that as small as the Pinball community is, it is difficult to find judges could be viewed as neutral. The door prizes potentially benefit all attendees and not just a handful, so we keep doing them. We increased the number of door prizes after we couldn't continue the game giveaways. We are considering many options. We are considering a drawing for cash or a prize for those that preregister and keep their game there all weekend. (We need to verify what is legal and acceptable) What is now happening on Saturdays is what happened previously on Sundays and is the primary reason there is no show on Sunday anymore.