Obviously not of the same gravity, but a good part of my childhood was spent being called by my big brother's name. Family, friends, teachers, you name it. It's a hard one, because I think my brother is an amazing guy, and evidently so do other people, but it's ultimately belittling. A math teacher, who had my brother for a single year, called me by his name for the whole three years I knew/had her. By that point, it…
This has happened to me a lot in my life--in fact one of my high school teachers called me my brother's name the entire school year. But I didn't feel belittled. Some people are just bad with names. I've figured out how to break people of the habit: call them the name of their sibling. This fixes it real quick like.
It happened most class periods to somebody, and that was with him being very deliberate about asking people to point it out and trying very hard not to do it.