Consider it a light preview of the chaos is to come when courts get involved and make rulings about required transfers of assets and decide to hold people in contempt when they claim they technically can't transfer them.
The inability to undo financial transactions based on ownership claims instead of hard currency flies in the face of centuries of expectations of modern society.
Evidence of past ability to undo transactions via hard-forks will create "interesting" legal conundrums for anyone trying to claim to a court it can't be done.
In practice, courts will say "pay the expected value of replacing the loss in USD", as they've always done for transactions that can't be undone. Permanent transactions are not a new thing to the legal system - if, for example, you sell a one-off art piece to someone else, then they sell it to someone else, and a dispute arises between the first two actors, the solution could not be to return the art piece.
For monetary transactions that's fine. But they are not the only type of smart contracts. Consider the people trying to e.g. bootstrap systems for using the blockchain as a share ledger for a company for example. There the court will just say "X is the owner of those shares. Ensure the record reflects that." If the system they have chosen for the ledger can't let them rollback a transfer because of a bug, that is the company's problem.
There are a lot of potential circumstances where people will need to find human workarounds for the supposed immutable nature of these blockchains because courts will simply say "this is how it is; make it happen". The above example is "simple": The company can worst case just pass a board resolution to replace the ledger and/or reissue it.
But it is a demonstration that the immutability of the ledger will often be irrelevant, in the face of a court that says "this is the truth now".
The inability to undo financial transactions based on ownership claims instead of hard currency flies in the face of centuries of expectations of modern society.
Evidence of past ability to undo transactions via hard-forks will create "interesting" legal conundrums for anyone trying to claim to a court it can't be done.