“It wouldn’t matter. Seoul would be wiped off the map in one salvo. The issue is not how long it would take to react, but to detect hostility before it commences and wipe out the threat.”
Renovating scores of artillery bunkers is something you do right before an attack. I would define that as “hostility”.
Well, they can wait for a strike or act. Under current leadership, I don’t see a good decision being made.