Idiots are idiots. You can't blame them for screwing up.
I very rarely hold a party whenever something awesome happens (Memorial Day BBQ, saber ninja got banned, etc etc), and whenever I do I notify people in the Gallery section at least a week ahead of time. This way everyone I do know and isn't an idiot will know about it, mark it on their calenders and jizz in their pants when they see nude blocko female bots standing on a stage with me DJing a dance floor, and etc fun stuff.
Basically, you need to let people know ahead of time, preferably on the forums so that people with an IQ greater than a squirrel will join.