This is a related topic, but not the exact one discussed here. I know a guy that was going to use the lavatory and opened the door to find another woman in there in a fairly compromising position...nonetheless I think they were both embarassed. The guy in a seat near the bathroom however did give the guy opening the door thumbs up. Hopefully no one has run into issues with the lock. Sometimes I know I've had to really force the lock to the right so it shows occupied.