DEAR MISS MANNERS: Sometimes I see patrons in a store or restaurant peer at the service employee's name tag and say something like, "Hello there ... Tiffany ... how are you today?" It always comes out with this forced conviviality, as if to say, "Look, everyone! I'm a good, egalitarian person treating the lowly server as a person. Isn't that great of me?"
I think it actually says, "You have such a menial job that you're forced to wear a stupid name tag, so I know your name and feel free to use it even though I don't know you -- but you don't know my name because I'm a higher-class person and get to dress the way I want."
I think name tags are just so you know whom to refer to if needed, as in, "I think Tiffany is our server. Could you ask her to bring the check?"
Am I right to see this as presumptuous behavior?
GENTLE READER: The presumption in the greeting you mention is not in using Tiffany's name, but in asking the waitress how she is "doing," a question about her mood or life that is not relevant to the business at hand.
Miss Manners has no objection to using a form of address that has been supplied by the addressee, even if, in this case, it may technically have been Tiffany's boss who chose the form. She does wish the form supplied was more formal, as she agrees with you that first names in this context are an invitation to mistreatment.