Just wanted to make something absolutely clear cause some people seem to be hard of understanding.
You are a legitimate (insert colour) belt when a legitimate black belt with a recognised lineage awards you said belt. The fact you are good, can hang with said belts, have beat said belts in competition does not make you a (insert colour) belt, only when you have been officially awarded your e.g. purple belt are you then in fact a purple belt regardless of ability.
I would rather have skills above my perceived grade than the other way around as at the end of the day it's about getting better. But if you haven't been awarded your grade legitimately please stop wearing it as it is embarrassing.