I think it would be a total succes to be able to condition whether you can take an item from a loot window.
For example:

Item had condition.

You can only take the item to your bag if you have X item.

Item destroyed.

You can only take the item if you have X ammount of Y item to be destroyed in your bag. This case can be done to set vendors on rol. For example you can only loot a sword from a loot window from a cuttscene if you can get "destroyed" 10 coins on your bag.

Thanks for your time ^^

Notes:
A loot effect could run a workflow when an item is being looted. The workflow would execute whatever is necessary (remove items from the inventory, etc.) and could also run a condition. If the condition fails, the loot is canceled.