A couple of months ago, I was the Captain on a flight to Tel Aviv. In Business was a man who's wife didn't wear her seatbelt before departure. The Purser approached them and asked the lady to fasten her seatbelt.
This is what happened:
Purser: Madam, can you please fasten your seatbelt for take-off?
Purser: Madam, please fasten your seatbelt. Attacher votre ceinture s'il vous plait, Maak uw stoelriem vast aub.
Purser now signs to the belt and gestures and says: Fasten your belt for your safety madam!
Husband: My wife does not speak to servants. and you do not tell her what to do.
Purser came to me, I went to the passengers involved and removed them from my aircraft for obstructing orders by the crew. They might have not wanted to talk with the "servant", but sure as hell neither would they be guest anymore onboard my aircraft. They accused me of the usual Antisemitic nonsence, but alas, out they went and I'm sure they won't be so rude ever again to the crew. People forget that crew onboard ship and aircraft have the safety as priority number one at all times. Onboard a cruiseship, the cleaner might well be the one saving your life incase of evacuation. Think about that.