Two groups NO ONE wants to tangle with: the Koreans and the Turks. Not only are they hardcore bada$$, but they don't give a rip about your little Geneva Convention.
Your view of the ROKs is right on. After a few sniper rounds would come from a village there would be no village. They operatd by their own rules and very soon the VC got the message not to mess with them. The could patrol safely at will.
Actually the Koreans are gentilmen, very nice when you get to know them, but they understand the meaning of payback. The Turks saved my uncle when he was shot down in Korea, I have a warm feeling for both.