There was a similar case a few years ago, where a guy made off with hundreds of thousands of dollars by exploiting a bug in a video poker machine. The casinos s

There was a similar case a few years ago, where a guy made off with hundreds of thousands of dollars by exploiting a bug in a video poker machine. The casinos sued him, claiming the money was fraudulently obtained. His lawyer claimed he had won by entering a combination of buttons that he was legally entitled to enter and so there was no fraud. The court agreed and the guy won his court case. Here, whether a court decides that his ether coins were fraudulently obtained is going to depend on how the court interprets the contract in question. These ethereum contracts are supposed to be fully integrated (meaning all of the contract terms are contained therein and no outside terms can be introduced). Since the attacker's actions were explicitly authorized by the contract (since the contract is the code), then it's entirely possible a court will find that it wasn't fraud. The really key question is whether the contract is integrated, which is basically the central contract law concept behind ether in the first place. However, I suspect a court would not be friendly toward the idea of eliminating dispute resolution. Especially an American court. It militates against many of the core common law and constitutional principles of American jurisprudence. I expect that a court will rule that the contract is void because of unilateral mistake. When one party misunderstands the terms of a contract, and the other party is aware of this and exploits it, the court will generally grant rescission (cancelling the contract and putting the parties back in the position they were before the contract, e.g. by transferring the ether coins back to their former owners) or reformation (rewriting the contract terms to reflect what the mistaken party thought they were). One can argue that the point of ether is to eliminate mistake and similar doctrines that account for human fallibility, but the court will probably say that you can't contract away a doctrine about contract formation itself. Anyway, it would be a super interesting law suit, and definitely would challenge many of ether's most important legal implications.