And enjoy your empty game hall. Who in their right mind would bring a game with that sword of damocles hanging over their head??

So your plan is more stick, less carrot? Good luck with that.

Your dedication is admirable, but sometimes it's not just simple tiredness that forces people to leave a show early. Some simply can't stay to the very end, and some of those people may want to bring games. Would you rather have a game available for play at a show for 90% of the show's duration, or would you rather have that game available for 0% of the show's duration? Stupidly draconian removal rules will result in fewer games in the long run.

Insisting that people keep games out until the very end of the show just reduces the pool of people willing to bring games. I really think you should go the other way. Have a best-of contest with a number of good prizes, game must be present at end to be considered. Maybe try a system where folks get no discount this year, but get free tickets for next year when their game stays til the end. Repeat each show and people who bring games will always get in for free, but only if they stick around each year.

There's just too many reasons someone may have to bail early to make early removal completely verboten.