I went on key club day in the fall... it was a disaster. They were all over every line singing a tune that someone taught them before hand. (and the lines were long - batman and riddlers were half hour waits twenty minutes after opening). And in high school, the cheerleaders were a lot more annoying than the keyclubbers, in general.
On the other hand, I went last sunday during purim fest and the park was empty until 1pm (other than the X and tatsu lines, predictably). But I would guess there are a lot more cheerleaders.