I dated a guy from Louisiana years ago (the reason I became a Saints fan) and he addressed everyone with Mr., Mrs., or Ms. and always said Sir or Ma'am even when they said not to. That was the first time I'd ever witnessed that!
Lol. I've been with my employer for 15+ years and I always respond to everybody here with Sir or Ma'am whenever they ask me questions or just saying Hi. One of the part owners of the company would always jokingly tell me "It's Sal, not Sir." I would always laugh. It was just so second nature to me, I could never change it. He tried for years to change what I called him, always telling me the same thing. Eventually he just gave in.
I don't really think it matters what you call people, as long as they know you're not being rude or trying to diminish them in some way. Although, I do prefer that if a young random person comes up to me to ask me a question, that he call me "Sir" or say something like "Excuse Me", rather than say some like "Hey, man." It just feels disrespectful to refer to somebody you don't know as if they are a buddy of yours, especially if you're younger than they are.