My friend let an ex from a relationship about a decade before stay at his place because she said someone had abused her and she needed a place to stay within a few months it became clear she had serious mental health issues, he gave her a formal eviction notice and pretty much lived in his room because she was so abusive and unstable just counting the days till her eviction date he even tried to find her help and alternative accommodation from social services but she refused to accept it.

The day before she was due to be evicted she phoned the police and said he had sexually abused her, he was arrested and spent the night in the cells when he was released he was told he wasn't aloud back in his house. He ended up having to rent someware else to live so didn't end up on the streets. Within a week or so all the charges were dismissed due to lack of evidence and the fact she was clearly unstable and seemed primarily concerned with avoiding eviction.

Its taken him about 9 months and about 30k in court fees to have her removed from his house, during which time he was required to pay all the utility bills which is fairly galling given she didn't even pay rent.

He was pretty lucky, it could easily have gone much worse for him, but despite everything going his way legally he still paid a massive price emotionally and financially.