Hmm, I didn't think about the calls that could happen. I don't know... I think if you have spectating-only people, it'd give people less of a reason to cheat for others, but some people are wild cards. I do have trust in a lot of other people, though.
If anything, I'd be fine with just hanging out and chatting during the pre-hours before the Games start, just to chat with some old friends.
Also, do you plan on having GameMasters? (There's another word for it, but I can't seem to recall it. The people who drop occasional traps or treats, something like that -- I'd be down to do that, too. You'd need some moderation in it, though, because if memory serves, didn't it go completely wild in one round or something? If even, or it could just be a memory from something else...)