If a pirate loots a stackable that he already has some of, how does the system distinguish between the two? especially once he merges stacks. Is the piarate then to be prevented from selling any of that stack?
It would need to prevent stack merging, effectively making looted stacks and unlooted stacks separate unique item types. I see this getting very messy.
I would love to make things more difficult for pirates but I dont think this is the way to do it.