I used to live in a city with pretty good tenant-landlord rules, policies and procedures. They seemed to take both parties' needs into consideration., and had user friendly mechanisms in place for swift resolution of conflicts. Still my kids and I were evicted from our long term home because one of the very few reasons a landlord could evict tenants was if one of their own family members wanted to move in.  Someone's kid would move in for a month and then change their mind... 

The tenant had recourse, but they'd have to move no matter what, then they'd have to spy on the new tenant to document what was happening, and take the landlord to court, etc. 

It's tricky, even in a place that largely gets it right.