Reading your numerous forum posts about D'Hara and its amazing trade I always wondered how much are you really able to gather. Almost every realm on dwilight struggles for food: very few have surplus and since food it's an insanely powerful strategic asset, food market is strictly controlled in several of those realms. I would bet that all lords or traders caught selling food where they are not supposed to is a free ticket for a ban almost in every realm of dwilight. Certainly you can have a few traders on your paybook that run around and steal food or perhaps some lord that sells to you without being noticed, but these would make such tiny quantities as to be completely irrelevant on the large scale. Also, not so many lords are playing the selfish greedy guy, I guess there are quite a few that would gladly sell food cheaply to their own duke without thinking twice.
Food transactions are invisible. Some places have no-trade policies on realm level, while we are finding very interesting deals there at region levels. We don't advertize this to their council, so it passes unnoticed to everyone but the lord.
Paisly is importing more food than it consumes currently, but it did have its stores depleted not that far back. Port Nebel is frequently depleting its warehouses, but it seeks out markets less and it seems the eastern markets to which it has access to are rather closed. Port Raviel isn't faring as good as Paisly, but it's getting there as they are multiplying imports as well. I, for one, always have like 10 active caravan missions. Port Raviel is starting to do the same. Our traders stop by every now and then with very large sums of food they purchased from lands our automatic caravans can't reach.
I don't think many realms would react as strongly as you describe to lords exporting their food, even if there is shortage within. It's hard to justify a communistic approach to food on the SMA island, and after all all realms welcome the additional gold the trade brings, even if it means their surpluses are significantly smaller.
We aren't using the black market as far as I know. Dwilight is big, there are still enough open markets to not have to rely on the black market.
