You’re ignoring the obvious answer. One that is also based in the real world-
The cops look the other way.
I was curious about this one year. I looked in my Yellow Pages under “escorts”. Then, I looked at the newly arrived this year’s Yellow Pages. The ads were the same. The same companies, the same copy, the same numbers as last year. Clearly, the cops had decided not to bust any of these businesses.
Vampires can be centuries old, with massive wealth and influence. It would be easy for them to bribe the right people, or blackmail them. Only the very rich would know of the bordello’s existence (heck, realistically only the very rich would know of the restaurant’s existence. OTTOMH I can name one five star Philly restaurant and know of one exclusive club for the rich here). Only very powerful cops and well placed politicians would know of the bordello’s existence. They would not know that the prostitutes are vampires.