My daughter cheered with Pop Warner - pre-teen to early teen. Pop Warner has strict rules around a curfew, I think it's 10pm with a bed check. A lot of the cheer teams stay at the moderate resorts, a lot of the football teams stay at All Star Sports. My experience is the cheer teams require one adult chaperone per cheerleader, I don't know about the football teams, but based on what I've heard that wasn't the case. We heard many horror stories about unsupervised football players at the value resorts but never experienced anything at the moderates. The teams tend to arrive a couple of days ahead of the competition, practice in the mornings and attend all of the cheer competitions prior to their own (older teams attend the younger sessions.) We never made it to the parks before 2-3pm. Many of the competitors left the day following their competition - we were always slotted the first week of December and generally stayed through the weekend following.
Pop Warner cheer girls (and boys) are generally very excited to be at Disney - like every other kid - and they get to visit with their friends and teammates. You can hear them in the parks chanting/cheering but they are way, way less obnoxious than some tour groups. You'll usually be able to point them out by their practice shirts and bows. I never experienced any obnoxious park behavior from cheerleaders in the 4 years we attended - but I can't say that about all park guests.