Networkview on prefab consumes bandwidth or safe to use?

When I have a prefab with a networkView and drag it onto a script variable so I can instantiate it from the script, will the new variable count as an instance and use bandwidth for serialization even though it's only used for instantiating other objects and the original prefab is never modified in any way?

I have many prefabs that are dragged onto scripts in my game, but only a few actually end up getting instantiated (player chooses which ones), so I only want to consume bandwidth on the ones I actually instantiated.

Do the scripts attached to prefabs even run at all?