People come from all cultures and plus they keep changing the rules on us. In Vegas, first you were supposed to tip your host or at least buy him a gift and now it's a bribe to tip your host and a gift is probably in poor taste also but it's OK to tip the clerk at the desk to get an upgrade and by God if you don't tip everybody else you're rude. How do you win? I would not embarrass someone for trying to slip me cash. I would just slip it right back with a quiet face-saving comment. Believe me, no one is offering you money because they want to offend you. You are painfully aware of the airline's financial issues because you work there. I guarantee that if you stop Joe Average on the street, they don't got a clue nor would they quite see how upgrading someone to an otherwise empty first class seat is hurting anything. I guess I don't quite see it myself. A polite "it's against the rules for us to accept tips" is fine and I'll accept that answer. Since you are not a public official, it ain't a bribe. It's a tip -- and if you are not allowed to accept it, that's cool. But it was never meant as an insult or to cause you pain. I'm quite sure you are a professional and that you do a fine job without needing to be bribed. Sometimes people are imperfect and simply do not -- cannot -- know the proper rules for tipping in every situation.