You have to become smart mouthed. It's the rule of survival in the airport. Ground staff may have problems with very rude passengers. The former ground staff at heathrow recalled she was politely checking a man into his flight when her collegue was having problems. A man was calling her some horrible names because his baggage was overweight and she was charging him (hint: it wasn't very much overweight, and if he'd been nice about it, she'd probably have let him off the charge). At the end of his diatribe, in which she was sitting very calmly, making eye contact, she asked him if he would kiss his mother with a mouth like that. She suggested him to go away until he can behave his age.
So you'd better be nice to ground staff.. You can't see what goes on behind that little desk of theirs, what messages they're putting into your booking about you..nice as well as warnings. If the gate and cabin crew ultimately get a nice message-they will act upon you. Now you know!