I don't think they will do that, because that's more of an American doctrine. The Americans do it because
1) America is geographically isolated, they can bomb you with little risk of the bombs coming back the other way.
2) They only do it to people on the other side of the world
3) and/or They only do it to people too weak to retaliate.
e.g. America will bomb the weaker nations in the middle east, asia, or latin America
only. There's a reason they've only ever directly attacked Panama, Grenada, Guatemala, etc. Because those nations are
very small. And if the biggest most powerful nation in the world only has the balls to bomb countries about 1% their size, then NK would need balls of fucking steel to bomb a bigger and richer nation than themselves.
Remember, it comes down to
oil. NK consumes less than 0.1% of the oil that SK consumes. They'd last about a day in actual combat. They still use WWII trucks I believe.
oil bpd is 2.5 million for SK, and about 20,000 for NK. A bbl is 160 litres, and a
Mig-29 would apparently need 770 litres of fuel in the first 5 minutes of flight. So, in other words, each air-minute they have a fighter up there costs around 1 bbl of fuel out of their entire national consumption of 20,000 bbl / day. If they send 10 fighters up for a 20 minute flight, that's 1% of their entire national fuel consumption for the day, whereas 1% of Sk's oil consumption could put their entire airforce of 700 planes into the air for 35 minutes.