It's unfortunate that certain gymnastics types moves are banned, however I have noticed that many of the stages that we get from hotels are so terribly unstable that I fully understand why they don't want to allow those kind of activities on the stages. Typically, the stage is made of a set of 8'x4' "tables" that are merely pushed together. If you're lucky, each panel of the stage is linked strongly to the next, but don't count on it. I suspect that's why the gymnastics type moves are prohibited: it's HOTEL LIABILITY... (In other words, the cosplay director has no say in allowing /disallowing such actions, but the hotel can forbid certain activities and substances from the stage just because they don't want to deal with any possible liabilities that could be created by such things.)
Oh, the Cosplay rules have been ready since late January... I'm waiting on Web master to post them [hope he posted them; check the main site]. The rules are essentially unchanged from last year, so if you have last years' rules, you're good to go [there were a few changes, but nothing major changed].