I'm wondering if hotels will be requiring ID (and/or showing of room key) for entry on NYE. I wouldn't think they would let in just anybody.

Also, even if you are successful in finding a bathroom, you may have trouble getting back to wherever you were standing. According to themicah in the thread I posted above (Times Square on New Year's Eve), once a "pen" is full, you can leave, but you might not be allowed back in!