Not that I've ever seen. The party is down on the lower level (to your left heading towards Tomorrowland). There might be a bit of a cluster right when folks are waiting to get checked in but I'm certain I've walked through the walkway part of it many times during parties. I would recommend against those restrooms though as the women's room at least only has 2 stalls and waits can be long, especially during a party. I'd go down to the ones closer to the Plaza which are normal sized ones.