Some possibilities for black market trading opportunities under the new trading system:
3) Skimming gold from the transaction by shorting the seller, then pocketing the difference. The challenge here would be to try to hide it in some way that is not obvious. Perhaps a delayed message about a shortage in the trade balance in the next tax report? You couldn't charge the buyer too much, as the money has to come from somewhere. To fleece the buyer, see the next idea...
4) Trading on mismatched offers. I.e. matching a 400 bushel Buy with 350 bushels of Sell, and pocketing the difference. As above hiding the mismatch would be difficult. Delayed message in the Harvest report? You couldn't short-match the seller, as that would leave bushels floating around in limbo.
All of these could have varied risk levels. The greater the risk, the greater the potential profit. Failure could result in confiscation of the food and/or bonds by either the buyer or seller, or maybe even arrest of the trader by agents of either party.
What about the Lord is informed of a deal done but he gets a message that says "300 bushels were sold for 30 gold but xxxx gave us bottle caps instead, so we basically lost the food (or vice versa for selling)" where xxx, when the skill check for the trader is successful, is a random name (or one can just say he faked identity so we don't know who he is, like in infiltrator attacks).
Everyone could have done that, lord has no clue who could it be. It should be regulated to make it not too powerful and increasingly risky with the size of the deal perhaps, but like what was happening in the old system a trader dealing on the black market must also be smart enough not to be the only one potentially responsible for food disappearance and do it in the right place at the right time.
