To be honest - it's about neither group trusting the other anymore. I quit assuming anyone coming from the north has purely RP intentions years ago and not -once- a return-visit was greeted with more than two words. Followed by a hailstorm of gunfire.
It's kinda like fool me once, fool me twice. Well it's been a few hundred times by now and nobody's taking any chances anymore.
Solution? Peace. Preferrably by removing the T37/alpha hole.