I'll bet just threatening to double the rent is a crime.
I'm not a lawyer, so I wouldn't know that.
If it's student housing, then it's not a stretch to assume that either the lease was signed before the student was married, or she signed the lease knowing full well that they might be violating it at some point in the future.
Maybe, maybe not, if it's based on occupancy. The baby means the population doubled, with Dad coming 'home', tripled. An awful lot depends on the terms of the lease.
No, I'm not arguing in favor of the landlord, either.
I'm just saying that it doesn't seem as if we have the whole story.