During WW2, countless featherheads (I believe that is what they were called) were deployed by the US to Japanese citizens, telling them it's probably a good idea to leave the area. Citizens were warned in advance as well. I assume we'd do the same in NK if that were to happen, but how would we do it? It's NK after all.
That was applicable when mutually-assured destruction wasn't a factor.
Even without considering that, there's one thing that North Korea is definitely prepared and logistically capable of doing and that is turning Seoul, a city 10 million people (surrounding metropolitan area 25.6 mil) into an ashtray. Throughout recent history, that has consistently been their one significant bargaining chip and you can count on them having perfected that ability.
That further confirms the inevitable fact that while N Korean military capabilities are often ridiculed, any military solution against the regime would lead to a catastrophic civilian loss of life on both sides.
