When visiting someone, I always take my shoes off. If the person I'm visiting says "No, it's all right leave your shoes on..." then I do. I expect the same of my guests as well, but I have never had someone just leave their shoes on and walk around my house. (probably because I wouldn't let them get that far )
I think it's just a common courtesy that I was raised with, and I expect most of the people I know in my life are the same...
Dottie