I've organized the repair team at the last 3 Pintastic shows, and spent the majority of the time from 8am to midnight in the free play room. While I certainly didn't see everything that happened at the show, the majority of the offenses I did see were folks sitting drinks on the playfield glass (I think a lot of this happens later in the day as the booze starts flowing more freely). This is where we rely on the attendees to inform the show staff of abuse - the phrase "If you see something, say something" is very appropriate.
I know it can be hard to see staff members in the sea of attendees, and next year I'll push for brightly-colored fluorescent vests for the repair team. The current rules poster at the entrance is also WAY too lengthy, and we'll work to condense that - and have more informational notices on display.
Let me also throw something out to everyone who lives in the area where a show is hosted: There's always significantly more work than volunteers (and volunteer hours) available; consider volunteering at your local show, and there will be more eyes to watch over the games and help police bad behavior.