A very interesting question: I've stayed in thousands of hotel rooms during the course of my 23 year career with AC. Of course, the hotel bill has always been picked up by AC.
Much the same way that most business travellers hotel rooms are paid. By their company.

As an example, AC utilizes Hilton in a large number of cities. I have never once received as much as a free lunch from Hilton. They never offer me free cocktails, free food or anything approaching what an airline offers its frequent customers. Perhaps I have been satisfied up until now, because the courtesy has never been extended. I would probably rank among the top tier of Hilton frequent guests, if a count had been kept.