Rumors require a certain degree of communication and thats something our gym has problems with, so I would say rumors are minimal. There may be gossip going on, but most of the parents aren't around all that much to start it or follow up on it. If there is any gossip that gets going its from a couple of moms that work part-time at the front desk. They have a little trouble learning when to stop talking about things they hear in the gym.
We also seem to have the "clique" thing going. I thought when my daughter moved from pre-team to Level 5,(we don't have Level 4) people might actually say hello. Parents on the team talk with each other, but there is a major division between the compulsory and optional parents. Funny how fast they forget their daughters were Level 5/6s only a couple of years ago.