If they're shared tenants in a building owned by a landlord, they need to report the Airbnb to their landlord, followed by a notice-and-cure letter demanding that the landlord end the use of the building for Airbnb rentals. Conversion of an apartment in your building into an ad hoc hotel is a material change for any number of obvious reasons.
Comments
..DID talk to those visitors..
They need to talk to the person the visitors are renting from. Is that doesn't work, they can go one level higher up.
If they're shared tenants in a building owned by a landlord, they need to report the Airbnb to their landlord, followed by a notice-and-cure letter demanding that the landlord end the use of the building for Airbnb rentals. Conversion of an apartment in your building into an ad hoc hotel is a material change for any number of obvious reasons.