I think I got backed off once, but it was so gentle that I'm still not 100% sure what it was. A pit boss approached me and offered me an unsolicited comp for the buffet. He said something along the lines of, "You've been playing for a while, why don't you try the buffet on us? Just sign up for a player's card ..."
I just agreed that I had been playing too long, cashed out immediately, and then scurried away with my tail between my legs, crying, paranoid that a SWAT team was now tracking my every move.
(Okay, I wasn't crying.)