these days i try to pretty much avoid rank altogether.
back when I was training in a lot of different things, I always wore white belts, if any belt at all, when starting a new style. I had some instructors who thought that was a little weird, but then again, what else was I going to do?
nowadays the only times I wear belts are when I have to:
kenpo BB when teaching kenpo (I'm not the head instructor, so it's not my rule...)
arnis BB if I'm asked to (formal testing, etc.)
BJJ blue belt to hold my gi closed.
anything else is no belt, or if I have to wear one, white belt.
The only exception was one instructor who insisted that I wear the highest rank I had earned. His thing was that he was teaching concepts, not specific technique, and that he would rank the other students in TKD since he also taught that. But we were studying other material with him, so he just wanted us to wear whatever our base style had ranked us as.
~TT