There are some places, I'm not sure how common but my guess would be "rather common", where it's illegal to have > x (where x is usually 2-4) amount of non-rela

There are some places, I'm not sure how common but my guess would be "rather common", where it's illegal to have > x (where x is usually 2-4) amount of non-related people living in the same residence. This exists where I live (but it was recently put into effect about a year ago, so it hasn't yet been enforced).