My observations would say that they did a good job of clearing out non party goers. I was not there to "police" folks with out wrist bands, but when I was in a line of people, I did notice lots of orange.
The park was certainly clearing out when we arrived at the parking lot at 4pm - there were tram loads of people - full - like you normally see at closing.
The park was very "quiet" in my opinion from 4:30 when we really got in the park. There were two girls riding in on the monorail with us who did not realize why the park was closing early.... the one was sure the
MNSSHP did not start until October!
In my opinion - I rather liked the parking staying open - we were not sequestered in one area and were able to continue riding rides. From the time we entered at 4:30 we:
shopped a bit in the Emporium
4:45 - walked past castle
5:00 - Grabbed a bite at Cosmic Rays
5:30 Finished riding Indy Cars twice
6:00 Finished riding Buzz - three times
6:30 Finished TTA - two round trips and walking towards Liberty Sq
6:35 reached HM and waited to meet another DISer ("ryanally")- DD rode while I waited outside - chatted with them a few minutes
6:50 - Rode Peter Pan (10 min wait)
7:03 - Took first picture at Dance
We did not do much in the way of rides after the party started - DD rode Goofy's Barnstormer while I went into Minnie's House (I did not realize the line was so long, and figured I would wait for her to come in, but I got caught up in the line of people, and she "excused" her way through to find me.... (accidental line cutting?) -
The sign at BTMRR said 5 minutes, but when she went up she said it looked much longer and she did not wait (we were in the midst of a "tiff" at the time - so she was being "difficult"!).
Next party I want to hit Toontown for the other characters & then ride rides..... we got the fireworks and parade out of the way and are staying at the Poly, so no need to drive home! I of course would not mind watching either again, but will pass if we can get some more rides in! It was nice watching the parade from the train station platform we got up there at 10pm and got a little table. DD played with some Fairy toys I bought her, and we just chilled.
This is was our 5th party since 2003 - I did not notice the crowd level to be any different than other years - we have gone from mid September up until last year the weekend before Halloween.....