I don't think it's true that loads of people from Pop are crashing at the AoA pool. Just because a remark is overheard at one pool saying they liked AoA pool better doesn't mean that the person wasn't a guest of AoA at the time. Lots of folks were taking one day out of their vacation to try out AoA.
There's always one or two clueless people who don't know any better who break rules -- can't stop that. As long as the pool isn't so overcrowded that AoA guests can't enjoy the pool, I'm not going to worry about it. Disney wants guests to be repeat customer, and if pool crashing starts impeding on the AoA guests enjoyment of the pool, the guests will complain and Disney will take action to stop it.