South Korea Questions Boat Passengers From North

http://www.nytimes.com/2011/02/08/world/asia/08korea.html?_r=1&scp=2&sq=north%20korea&st=cse

The wooden boat with 20 women and 11 men came across the Northern Limit Line in the Yellow Sea at 11 a.m. Saturday, military officials said in South Korea. 31 North Koreans who were riding fishing boats got captured by the South Korean Navy in order to investigate their main purpose of crossing a border line.
North Koreans said that there reason is not to stay in South Korea; however, South Korean defense official holds the North Koreans to define a real purpose of this. In my opinion, it is a right behavior for South Korea to investigate further since North Korea has attacked South Korea a few times, so South Korea should keep their Navy in alart.