If this means ban as in prison, then I'm unsure what to say. Well, for the sake of improving the in my opinion almost non-existent effectivity of the dojo, yes.
If this means total ban, absolutely NOT.
As to the dojo..before it even got approved of officially, I told Calyx something: Endurance is what will be needed if you wish to walk the path of no harm to others.
(Not these words, but same sense)
That opinion was there and still will be there. And still is here. The dojo can brand people, can tell them to stop, but they shouldn't have the right to take any measures, even if it includes being farmed, if you follow the entire idea of it.
But since so many people cry for help and that doesn't get ignored, well, dreams exist, prison is alike to that, then yes. But it shows the flaw of the dojo not being able to sustain itself without punishment which immediately removes the attacker, which is really sad in my opinion.