As reflected in the update Zoner polcies, the NFZ has changed drastically. No longer do we care if you shoot one another within the NFZ. We only care if you shoot a Zoner or damage Zoner property within the NFZ.
I'll use Freeport 10 as an example. If a Bounty Hunter and Outcast want to shoot one another near Freeport 10. Skullz doesn't give a crud unless one (or both) of them hit the station or for some reason shoot a Zoner that is present.