Cultural differences apply
Well, I was watching a French medical program recently. They discussed a survey done in France and the USA on how patients wanted to be addressed by their doctors and other medical staff. The majority of US residents surveyed wanted to be addressed by their first name. The majority of French people surveyed wanted to be addressed as "Madame" or "Monsieur" without any mention of their first or family names.
In cultural studies, this is known as the "power distance". France has a high power distance. The US has a low one. (Ireland is lowest of about 120 countries mentioned in the relevant study.) There is a notion of hierarchy here, and it is not that clear how the hierarchy is viewed between crews and passengers. I suppose your mileage may vary. As a dual Swiss-Irish citizen, I remain confused.