Detecting who dropped Inventory Item

Is it possible to detect who the person was that dropped an item in a object inventory? I've looked through the inventory functions and do not see support for it. Would be nice if I could get a changed event (which happens) and then detect the person that dropped it so I can give them something in return after I verified what they gave me.

Using the sensors to detect who is standing near the object would not work considering you could have multiple people standing there.

The collision event doesn't get raised either. I know it's a reach but I was hoping that dropping an item inside another would qualify for a collision.

Looking at the owner of the item is out of the question, that gets changed to the owner of the object when it is dropped.

Any info or help on this would be appreciated.

Thanks

Have the script only open it's inventory for 30 seconds after being touched. The touch event will give you the person's key and name. After the inventory drop, thank the person that touched and who presumably dropped the items in. It's not a perfect solution, but pretty good.