I think it depends on what room you're in and how full the hotel is. Lurker has stated in several threads that in NYC once you're in a room, the hotel can't really kick you out. But they can certainly charge you rack or beyond to stay.

That being said, if you're in a standard room, and the hotel isn't full I don't see any reason why the hotel would put a roadblock up for you. The longer you stay the more likely you'll use high margin hotel services like dry cleaning and room service.

If you had a suite on the other hand, in particular one from an automatic upgrade, I can see the hotel extracting a much higher rate. Afterall, they have to comp something to another high value guest.