If this has happened to you, I'm curious to know whose names you have been called (and whose names you haven't been called).
I've been called my brother's name and he's been called mine. (We don't have other siblings, so he doesn't have any brothers and I don't have any sisters. I wonder if our mother would have been more likely to call me by my sister's name if I had both a brother and a sister. Also, I'm not sure if my dad has ever called me or my brother by the other one's name, but our mom would have had more opportunity to do so, since she was more often home.)
My mom has called me by both her sisters' names (both younger), but never by any of her brothers' names. My dad has called me by his younger sisters' names (especially the youngest), but never by his older sisters' names. (He doesn't have any brothers.) I think my dad has also called my by my mom's name.
In the case of my mom calling me and my brother by each other's name, I think it's clear she's grabbing names out of the "child" group. When she calls me by her sisters' names (but never her brothers' names), it sounds like she's grabbing names out of the "female relatives" group. When my dad calls my by his younger sisters' names (but never or rarely his older sisters' names), it sounds like hes' grabbing names out of the "younger relatives" group (which I suppose also technically accounts for calling me by my mom's name). Or maybe we could combine those two and say that my parents both call me names out of the "younger female relatives" group.
Also, my mom once called my brother by the dog's name. I'm not sure what to make of that.