Ability to disable drag & drop into playlists from file explorer

This folder named "Unassigned" keeps appearing in our root media manager folder on its own, shortly after it's deleted. I found out a couple months ago that this folder would be auto created after users found a way to drag and drop items directly into their playlists, which should not happen. I have been deleting this folder, and it keeps re-appearing even without users dragging and dropping content into playlists. Is it possible to disable drag and drop from file explorer into playlists?