Master blue. If you have to steal chalk, you are either too poor to play or a thief.
I don't understand why people are so against someone grabbing a piece of chalk. Many people are regulars at certain places. If I take a cube from my regular place and use it, I'm not using any more chalk than if I were to just use what they give me every time I go play. But I do get the privilege of a nice, hand-picked, clean piece that is already in my chalk-holder, rather than having to sort through some riff-raff pieces every time I go play.