I’ve come to realize that the South is incapable of mounting an actual harsh retaliation, mostly due to their aversion to killing their own distant kin who are now brainwashed and waving little red books, but kin nonetheless. This is also why when we’re on the cusp of being able to starve the Norks into submission, the ROK howls and relents or even ships food “under the table” to the Norks.
That’s not entirely true. The South has responded decisively to naval violations in the past and would probably lash out if it is pushed. Mushy sentiments aside, South Korea fears the impact of conflict on its economy. It’s the same reason nobody wants to do anything about Iran or Pakistan.