Allen suggests that there should be a two thirds majority, but not what mechanisms could be employed should such a situation arise.

That's a good point, Fiona. I think it deserves more thought. There is a blockchain-based mediation platform that looks interesting. It's called Kleros. They incentivize adjudication on disputes similar to this. I've considered joining, but haven't pulled the trigger yet. I do think it's an interesting idea, however.