In some respects this is particularly useful in a criminal setting due to the US legal systems doctrine of un-clean hands. You can't sue your drug dealer for failing to deliver as agreed, for instance. As such, the blockchain is effectively the stand-in as you can't get sued by your counterparty over illegal transactions anyways, and the judge won't order you to reverse them.
But if you are dealing drugs, and the judge says to hand over the funds, you better believe that no amount of "blockchain" will keep those funds under your control.
