It's not a problem for the region--at least, it's their own fault if they set their sell orders in such a way that they starve.
As for traders, well, we're few enough as it is. Automated caravans can beat us to the spot as it is already.
Most nobles aren't going to want thousands of their gold tied up in foreign regions for weeks, if not months, waiting for food to become available. So there's room for traders.
If it's such a concern, perhaps it could be coded in a way that gives people at least a turn to buy the food before the caravans grab it up.
