carry yourself like you don't do BJJ
Guy walks into a Judo dojo. Neck slightly bowed, face impassive, wearing a knit cap. Eyes serene. Calm, cool, collected and polite. His face and emeanor saying "I am confident. I can fight. I know BJJ".
Seen it a thousand times. Can pick the guy out in a crowd even if he isn't wearing his shirt that says "Knee bar" on it.
Walks into the back and comes out wearing his blue gi, blue belt, and patches.
Hour and fifteen minutes later lays crushed beneath the weight of a middle-aged, out-of-shape seven time junior national Judo champion.
Seriously. Fucking carry yourself like you have a life other than martial arts. Smile. Greet people warmly. Make jokes. Be humble. Don't be a douche. Even if you don't give a **** about anyone but yourself, why give away the fact that you have training?
And how about showing up and asking if they have a loaner gi and a white belt, dickwad?