All party go'ers are issued a wristband and ushered to Tomorrowland. Then they herd everyone w/o a wristband out of the park at closing. While in tomorrowland the CM's are looking for those wristbands. We had ours checked a few times (if they weren't already visible). It was a really efficient process believe it or not. There is NO way to stay in after closing w/o purchasing the appropriate ticket.