Thats pretty obvious to me. The renter should have asked "what are all these signs"...
Unless we are talking about about a place like Fuji building where most of the building is occupied by hookers, you will not be able to tell the difference between a regular old building and a building that has a few prozzies in it.Um, I don't know....noise, drugs, violence, smoke, ciggy butts everywhere, people coming in and out at all hours, people hanging out in the halls.