I’m often on the opposite side of your cashier experience.
For me personally, I appreciate the polite gesture and understand the automatic nature it can be for some, especially southerners. So unless I can tell that I’m being “sir’d” with someone who has clocked me and wants to show their smoothbrain, then I don’t care much.
That said, I like the general idea of treating everyone with a nonconfrontational politeness, so I’ve been replacing formal pronouns with chief, coach, Bud, comrade, etc. Its ended up being even more disarming for most, and has a nice side effect of reducing the amount that I get misgendered.
Hope it helps, Have a great day chief!
That last bit hits home… hard