Someone has to clean up those roller coasters and all those other fast going, spinning rides after a day of people losing their lunch on the ride at amusement/theme parks. As well, upkeep and cleaning all over the park would be a dirty job.
actually me and my wife worked at Cedar point in sandusky ohio. This is not really done at night. If someone gets sick on the ride it is cleaned up immediatley. At night the grounds surrounding rides are walked by employees to pick up anything lost. The worst thing would be working for park services at night when they collect all the trash from the cans around the park.