I don't think a judge or the legal system is concerned with such a thing. That is a problem that Ethereum would have to solve, if it can. That said, the blockc

I don't think a judge or the legal system is concerned with such a thing. That is a problem that Ethereum would have to solve, if it can. That said, the blockchain is always going to be consistent. The catch is that a judge can still force things to be fixed in various ways - either by requiring you to return the ether, or perhaps requiring another type of currency to be given back. So in that way it doesn't really matter what the state of affairs on the Ethereum blockchain is, because you can just settle it apart from the blockchain if you really have to. And the reality is that you could make those coins impossible for you to access, but that doesn't do you much good, and while your ether is inaccessible the judge can seize your assets and require payment through other means.