They run the busses early and at the gate they have a list of everyone who has a PS and they check your name off the list.
We were there for the opening ceremony and we loved it!
However, do plan on at least an hour to get there. It does take some time to walk from the gates to Norway. We planned on leaving an hour before, ran a bit late but got straight on a monorail with no waiting. It was a beautiful morning and I didn't mind waiting in Norway for a few minutes. I got some nice pictures my DD's without any other people around.