Awesome French

Would you personally correct an American who used "tu" instead of "vous" when speaking to you?

Absolutely not, I don’t mind it at all.

However if the person is being obnoxious and/or disrespectful, I’ll correct immediately to remind him/her to treat me with respect. That’s the only case. And it has nothing to do with the person being American or not, this is something I do even with French people, when they are doing something wrong like trying to flirt with me at my workplace for example. Using “vous” implies a sort of safety distance between two people, which can be really useful sometimes…