Leases tend to be very clear about the scenario you describe. Ditto for city and state rental laws. Sure you can add family to the lease in NYC. I never said o

Leases tend to be very clear about the scenario you describe. Ditto for city and state rental laws. Sure you can add family to the lease in NYC. I never said otherwise. But if your sibling is repeatedly violating the provisions of the lease, and being a nuisance to the other tenants in the building, you can both be evicted. A landlord would rather vacate a problem tenant than have multiple non-renewals due to the nuisance. I mentioned that I've never personally encountered this situation because I sincerely doubt this is a common scenario here in NYC. Apartments are quite small in Manhattan. Most people have enough sense not to allow a sibling with a drug problem to live in their already-cramped living space long-term. Regardless, I still don't see how any of this is comparable to transient AirBNB renters being disruptive to one's neighbors. In reponse to GP's claim that this law is only helping hotels, I provided a personal example of whole-unit AirBNB renters negatively impacting my quality of life, in violation of the lease and now in violation of the law as well. You're responding with hypotheticals about a completely different scenario (long-term guests and/or adding people to leases).