The Zoners and the Harvesters may go to war in any release of the mod. Their Junker affiliation allows it and their shaky association with the OPG doesn't dissuade it. The Harvesters are technically a unique faction, though they've chosen to adopt the Junker ID, it's their prerogative if they wish to engage hostilities with the Zoners so long as they mind server rules in that pursuit.
What the Corsairs, in turn, do about the OPG's reckless affiliations is their own concern, one for which they may have to answer if they find themselves granting aid to one of the enemies of humanity.
I believe this is called RP and the development of a storyline by some people.