I doubt you'll find much legal precedent (or published rules on the exchanges) supporting your theory, except in the case where a broker makes unauthorized trades on a seller's behalf. Feel free to prove me wrong...
When I say I have seen it I mean I have seen it first hand. I have worked for banks where trades were unwound with the counter-party for this exact reason. The implementation is messy, but no bank on the other side of a trade wants to be party to trafficking in stolen goods resulting from a fraudulent trade.
What happened here is akin to me logging into your brokerage account with a stolen password and selling all your securities. This happens and those trades get busted. Sometimes the selling bank just eats the loss as it would take too much work or too much embarrassment to recover, but other times they work with the counter-party to unwind.
I'm not asserting this happens in all cases. As I said above, IANAL. I know equity laws in particular are a bit different than a lot of other types of property which fall under common-law.
That is kind of moot though as equity laws don't apply here - bit-coins aren't equity.
Also, you're talking about counterparties cooperating because they do many transactions together at the institutional level. That's different from the exchange itself voiding the transaction.
What happened here is akin to me logging into your brokerage account with a stolen password and selling all your securities. This happens and those trades get busted. Sometimes the selling bank just eats the loss as it would take too much work or too much embarrassment to recover, but other times they work with the counter-party to unwind.
I'm not asserting this happens in all cases. As I said above, IANAL. I know equity laws in particular are a bit different than a lot of other types of property which fall under common-law.
That is kind of moot though as equity laws don't apply here - bit-coins aren't equity.