I have a tenant who has been living in my garden house for two years without paying rent. It is almost impossible to solve this situation. I am not even allowed to turn off the water or electricity. There are always two sides to every coin.
It was the neighbour whose house had burned down, and my mother let him move into our garden house (because winter was coming). They agreed to make a rental contract. But after he moved in, he refused to pay anything and since then it has been impossible to change that.
In Germany you have to file an action for possession ("Räumungsklage"). But that takes years (I brought it on its the way immediately). You cannot act on your own, it has to be legally enforced. But the legal system in Germany takes ages and human rights are higher than tenancy rights (usually good!). This often leads to deadlocks where nothing happens because you cannot evict someone and put them on the street.
Another case where the ‘winning move’ is to either have enough money small issues like this are in the noise, or no money at all (on the books) so society goes out of it’s way to not do anything.
Also known as ‘on both ends of the economic spectrum exists a leisure class’.