Yeah get used to it! My older kids are 5 and 4 now, and as they get older it is harder to just follow behind them and monitor what is going on every second. It really is very shocking what some kids are allowed to do. I've ;earned that saying something to them or the parents is usually useless...although I will anyway. We end up just having to leave or move to another area if there are bratty kids there.
I asked some kid who was climbing up the tunnel slide with a MEDAL ROD to stop before someone got hurt the other day and he yelled down "I'm 11, and I can do whatever I want!"