What happens if a trade that is illegal under the law of the country of the sell...

asynchrony on Oct 11, 2018 | parent | context | favorite | on: SEC tightens the noose on ICO-funded startups

What happens if a trade that is illegal under the law of the country of the seller/buyer/exchange? The courts would be completely powerless to undo the transaction. Again it seems to me the main and only attraction is evading regulation.