I was there until a few minutes after 7pm without a wrist band.
The only part I found annoying was the herding out that started BEFORE 7 pm. That was insulting. I wanted a particular picture before leaving and they wouldn't let us walk through the park "the other way." I knew we were getting kicked out and that was fine - but I expected to have free rein of the park until 7pm. That's my only complaint. We did pay for park admission that day and I expected to be able to walk around freely until then.
That said - we were at about Casey's at the top of Main Street at about 7 pm - and it was clear we were going to only be allowed ONE way - which was fine because that's what we were expecting. But they weren't too pushy at that point, probably because we really were just watching the crowd and not one of the many still trying to jump around the person barricade. They did stop me from entering a store at that time, but they did allow me into a restroom - but there was definitely no backtracking at that point. We continue to watch the crowd pour into the park for the party from the area by Guest Relations until maybe 7:10 - and then left. There were still alot of folks not attending the party leaving, we were far from the last. It was a beautiful evening, the Halloween lights where on the castle, and those coming to the party were all decked out in costume. We got a "feel" for the party.
So - they are firm about it. If you aren't attending the party - expect to get ordered which way you are allowed to walk and which way you can't go as the witching hour approaches. They have ALOT of cast members making that exit happen. Some are more bossy than others, but all are there to enforce the rules. You won't feel welcome. And well, after 7pm - you shouldn't.
I did attend the party a week later in
Disneyland. We saw quite a few people without wristbands milling around after the party start time - more than I expected. But as the evening got later, those numbers went down!