I don't like the idea of using the Zoner ID. It's a similar situation to the Harvesters and the Junker ID. When people see a Harvester doing something, they'll either think "That's how a harvester behaves" or "That's how a Junker can behave". If one group of Zoners goes around killing pirates, then other Zoner ID holders might think its allowed. According to the Zoner background, they aren't hostile with most pirates. They in fact shelter and trade with them. This means if a pirate is attacked by an ATA member, he might consider all Zoners as hostile and to be attacked. Either way, it's bad for the non-ATA Zoners.
I'm fairly sure Zoner freeports would not like a renegade group messing with their carefully-crafted neutrality.