I think this is a helpful analogy for thinking about the recent Bitcoin Cash fork. Anyone can make a Dollar fork, and for people who hold Dollars in their native form, paper, this isn't a problem: you can choose to participate in the fork or not, mostly based on whether the fork ends up being worth something. On the other hand, what if someone owes you a Dollar, perhaps because you loaned it to them, or you deposited it in their bank? In the Dollar case this is very clear: they have no obligation to interact with Credits at all, and if they happen to give you back bills that have already been registered for Credits that's your problem. If they registered all the bills they held and kept the Credits for themself, even that would probably be fine.

Why is people's sense of what's reasonable different in the cryptocurrency case?