Wow, that many competitors!? Drunken Master sure seems to be popular.
Hmm...I'd think about being a judge, but I'd go with hiding my criteria. Mostly because I want people to surprise me, not please me. Also, it would make people think about interesting stuff without the worry of choosing one thing or another.
However, I'll probably be forced to unleash my criteria one way or another. I'd also be far too verbose as a judge, though that would allow a very stringent analysis of each build and how the fluff supports or bolsters the idea; look it at the full package. I find that, by looking at the judges' criteria, stuff gets lost: I don't recall Iron Chef (the actual Iron Chef TV programs, both in Japan and in America) judges ever reveal their criteria, other than "surprise me" and "this better taste good".
So...I'll let the organizers and the other judges decide whether I can be a mystery judge or if I'll be forced to show my criteria so that people attempt to "amuse" me. I'd rather see a risqué build, done with an idea in mind, rather than something to appease the competition. But then again, I'm not entirely free of guilt in trying to do that, so...