But understandable. I think the NK-watchers believe that the impending post-Kim era will not come quietly. And while it's not entirely clear what form the unrest will take, it's a better than even bet that there will be a military component, possibly or probably directed toward the South.
So, by necessity, they're starting to look seriously at the contingencies, which are unpleasant.
Note that there's a complementary military component to this.
A mass of refugees moving south, is mostly a problem if the defending military is either being driven back onto them, or if supplies and reinforcements are trying to move northward through the refugees.
To avoid that problem, I think the military plan would have to rely heavily on stopping the NK invasion early, and on keeping supply lines short and relatively forward.
It means establishing air dominance (which should happen quickly), and also making sure that enough artillery and other defensive preparations survive the initial bombardment to effectively disrupt and destroy the waves of invading NK infantry.
It works otherwise too: to be successful, an NK invasion would have to rely on speed, because it's almost certain that they will not be able to maintain their supply lines. They know that eventually they'll have to try to live off the land as they move south, and they want to forestall that for as long as they can. So it's doubly important slow them down or stop them, because they'll quickly starve.
Finally, it's imperative to establish and maintain naval superiority along the coasts, in order to keep open the crucial seaborne resupply lines and ports. Keeping control of the coasts and ports means that, even if the NK breaks through in the middle, they'll end up with long, exposed flanks, which can eventually be cut.
Note that none of this really applies, if the North Koreans' intent is simply to stage a götterdämmerung scenario. In that case, I think they'd just go for causing maximum destruction, without any real intent to follow up with invasion and occupation.
“So, by necessity, they’re starting to look seriously at the contingencies, which are unpleasant.”
Not just unpleasant, but unfathomable to this generation. We would be looking at an evacuation and destruction of a major/modern metropolitan area that hasn’t been seen since WWII.
Let’s hope it doesn’t get that far . . .