There have been two traditional methods of dealing with this issue. First off, the scalps were flagged as 'unstealable' on the creature file. This was the method which Kevin Dorner used in Baldurdash. However, it was learned that once an item is flagged as unstealable on one creature that particular instance of the item remains unstealable throughout the game. Those playing multiplayer wanted to be able to pickpocket the scalps from each other (I suppose for the fun of it). This lead to the development of the second method. This "newer" method entails moving the item from the inventory to an equip slot such as gloves/bracers where it can no longer be pickpocketed.
I suppose the "newer" method is fine, but I disagree with it in principle. I'm building a FIX pack which is designed to correct things rather than intentionally placing things in the incorrect slots. To that end, I've developed something that I feel works best for this situation. I'll include working .tph code in a spoiler for those who wish to take a gander. Also if any wish to incorporate this idea to 'add' additional scalps to other creatures in the game feel free.
The basics of this are as follows:
ALL scalps are removed from the individual bandits (manual search done on a Saga install to get the list)
Those bandits who turn hostile via dialog file have their call to enemy status adjusted to create the scalp and then turn them hostile.
Those bandits who turn hostile via script OR are hostile to begin with have the scalp created via a modified shout script.
What does this do?
It allows for the scalp to be pickpocketed from fellow party members in a multiplayer game. It allows for the item to be assigned at the time of hostility in a correct and valid slot for the item. It allows me to mod happily knowing that I didn't intentionally bork something to make some people happy
The code: