twinkletoesCT -
I've never been in BJJ circles that use it, but the karate school where I grew up used it plenty. It makes me laugh when anti-TMA BJJ-types use it, for that reason.
We have (had?) an older black belt who moved up here from Brazil. I have no idea what his first name was, because all his students referred to him as "Sensei" Salustiano. I hear he was very nice, and very knowledgeable. They liked that he used the title because they were fond of him and very respectful.
Yeah, I love it when the rabid anti-karate type of muay thai fans/practitioner use it aswell.