I've stayed at Pop Century when Pop Warner was there, several times now. It's really no problem. Yes, you'd occasionally get large groups of kids touring the park together, packing into the cafeteria or piling onto the bus, but that's true almost every time of the year now. If it's not Pop, its some band thing, or cheerleaders, or quincinaera (sp?) parties, or tour groups, etc.
Pop kids are mostly occupied with competition during the day, so they don't add to the congestion in the parks. And they're easy enough to avoid.
We found them very polite, the few times we encountered them.
The only problem we had at all was with one of the adult chaperones who, for some inexplicable reason, felt he had to start hollering at some kid at 5am. Never heard a peep from the kid, but my gosh Dad/Coach/whatever was loud, angry and borderline abusive. I don't know what the kid did, but I truly think the adult was the real problem there. He kept going on and on. If we'd been close enough to know which room they were in, I'd have called down to the front desk to send up security.