If you’re finding that binder items are being moved accidentally, I would strongly recommend buying a new track pad or mouse, or checking their sensitivity settings. 
Dragging in the binder uses Apple’s standard dragging code, so is no more sensitive than any other area across macOS that allows dragging (and I can think of nowhere that dragging can be “locked” to avoid accidental drags).
@SteveCarterFrogStory: those were wise words indeed. In this case, to disable drags in the binder, the side-effect would be that you could no longer drag Scrivener links into the editor, or documents into the header bar, or all of the other things that drag can be used for; or it might disable all drags into the binder from elsewhere too.
This one is a definite no, sorry!
All the best,
Keith