We were there December 5-11 and I will just echo what previous posters have said - we didn't see any effect on park attendance, although you may run into the occasional group of them. We never saw more than half a dozen at a time. The people who had the most problems seemed to be the ones who were staying at the same resorts as the Pop Warner groups. If you stay at a resort where they are not, their impact on your trip will likely be minimal, if not non-existent. I think that their group sometimes has one park, most often MGM, closed early one night for their exclusive use.