They were all done while there was a bunch of armed men in control of the exchange, I don't think there would be any doubt at all that any trades made within th

They were all done while there was a bunch of armed men in control of the exchange, I don't think there would be any doubt at all that any trades made within that time frame would be considered suspicious and not honoured. It would be unlikely he'd be out any money anyway since the clearing firms would probably refuse to clear the trades. (If you're not familiar with what a clearing firm does - they're essentially a middleman who ensures that a trade actually gets completed (settled) and at the same time reduces your operational risk by protecting you against the risk of a counterparty either not-honoring a trade, or going bankrupt before the trade is completed.)