My rental agreement (in a 4-storey apartment building) in SF forbids me from subletting (without consent), or from having overnight guests for more than N days

My rental agreement (in a 4-storey apartment building) in SF forbids me from subletting (without consent), or from having overnight guests for more than N days a year. Are most other rental agreements more lax or do many Airbnb hosts operate in violation of their contracts?