We're not pirating anybody while in Bretonia, we don't shoot BAF, BPA or any other Bretonians in, or outside, of Bretonia... and the last time I checked, the Bretonians has nothing against Cardamine carried for personal use, and thus we are not outlaws in Bretonia.
Now, as for why we would possibly aid the Bretonians... well, it's called taking an opportunity when one presents itself; The people they are shooting are more often than not Corsairs, Corsair sycophants, Kusari nationalists or SCRA insurgents... who just happen to be our enemies. It'd be quite dumb not to take the chance to destroy some possibly future pests, and perhaps to show the Bretonians that we are not as "evil" as the other houses would like to think that we are.
That is our official stance.
Now, if we're going to talk about "ganking" SCRA... I believe that several SCRA individuals has stated that it's okay when they do it because "it's part of their roleplay"... however I'm not going to emulate that behavior, and whichever pilot was involved in that won't be doing it again. It'd be nice if our enemies would return the favor from time to time though.
