Some people seem to be under misunderstanding about what happens to yellow belts. At first there were no green belts, so yellow belts could pick their dojo style.
Now there are green belts, that means when someone becomes a yellow belt 0, they can join a Dojo and pick one of the dojo's styles, as their dojo style.
Or they can keep fighting as a yellow belt, and forgo having a dojo style.
A yellow belt doesn't need to join a dojo to fight, but one does if he/she wants a dojo style.
Now there are green belts, that means when someone becomes a yellow belt 0, they can join a Dojo and pick one of the dojo's styles, as their dojo style.
Or they can keep fighting as a yellow belt, and forgo having a dojo style.
A yellow belt doesn't need to join a dojo to fight, but one does if he/she wants a dojo style.