A few years ago I had a concierge at the Hyatt Regency in Chicago tell me that he received a kickback from Cheescake factory and the Grand Lux Cafe on Michigan Ave. I had casually mentioned to him that I was thinking of eating there for dinner and he told me about the comission schedule and said that if I took his business card with him I could cut the line. It worked out for me since the hour wait became about 5 minutes and he got a little a something as well. I have no problem with these kickbacks as long as the the concierge is upfront about it.