This was technically the rule at my campus apartment in China, but the security guards never gave a
. Also, it wasn't in the contract, it was a building rule, and the rules were posted in the lobby in Chinese, so I could plead ignorance.
My apartment in Beijing was a full fledged after hours hotel. I'd put up entire rock bands (and their girlfriends). Never had any trouble.
Did come close, though. I was seeing this girl with some serious mental health problems and she moved in with me for a month. She was manic depressive, suicidal, ect., and I started to become terribly afraid I'd come home one day and find her hanging from a light fixture. Explaining a dead girl in your apartment is not exactly the way one goes about maintaining your job security.
Soo..yes, it is standard, but usually not enforceable. Just use good judgement and
away.