I'm an Internet expert too. It's all right to wire the industrial zone only, but there are many problems if other regions of the North are wired.
Any loss of identity prompts people to seek reassurance and rediscovery of themselves by testing, and even by violence. Today, the electric revolution, the wired planet, and the information environment involve everybody in everybody to the point of individual extinction.Marshall McLuhan
South Korea is an extremely wired country, so has a lot to attack. Unfortunately for the South Koreans, North Korea has extremely limited internet connectivity and hence is a target-poor country. Hence, the only option is [conventional] war - or convincing the North Koreans that they can attack them in cyberspace as well.