When I was working as an assistant manager in a hostel in northern Washington state (in the US) I had a guy check in who was so not all there. I guess he'd been in a car accident as a teen and it totally messed him up. This woman called me and asked info about the hostel and basically dropped him off.
Of course, I did have the right to refuse service. However, I did not want to refuse service to someone just because he was mentally not all there. In my opinion that is equal to refusing service because of race, religion, sexual orientation and all of that.
This poor guy. He kept asking all of the women on the hostel, including a woman in her 60's if he could spend the night with them. He wrote weird stuff on the signs we had posted about washing dishes. His father would call the hostel looking for him. He also drew on a goat skin drum that was in the common room. I finally had to remove him. I found out later that he had been kicked out of his parent's house for assaulting his sister and was waiting for a court date. It didn't help that we had some guests who were extremely self righteous and very biased and were pushing him to act up more. The morning I kicked him out he was running around in raggedy boxers being weird. Oh the joys of being a random hostel in a tiny town.