I've actually had the experience twice, but for the sake of time, I'll just tell the first one.
The first time was the night of the closing of the Big Bad Wolf. It was a good hour since the park closed and there were still a good amount of people standing in line for the front row (me included) to get that last night time ride "At the Speed of Fright". Anyway, I ended up on the sixth-to-last train after it started raining and night had fallen. After riding, we were basically free to go back to the front of the park on our own (at least that's what I assumed- no one told me otherwise). You would think that they would still have someone in the park, but after leaving Germany, we didn't see anyone at all until we got to the front gate. Even worse, all the stores were closed, it was raining, all the lights in the park were off, and there wasn't much moon-light because of the clouds. That is one of those things that I'll never forget. One of the other people with me dropped back five feet or so as we were walking through Italy and I turned to the other guy who was with me and said: "I'm pretty sure this is how all those horror movies start: A group of people is walking through some deserted place in the middle of the night and the girl starts to fall behind and then someone leaps out of the darkness and snatches her. Then we get picked off one-by-one..."