I stayed at this certain hotel several times and their rooms' AC's had a cover over the controls that you open by pulling it UP.

ALWAYS before sleeping, I will pull the AC control cover down. When I wake up in the morning I saw the cover was pulled up. The room was locked and I'm the only person in the room and it happened during different visits in different rooms. Whole place must be haunted, good thing the spirits are just pranksters and not harmful.