North Korea would likely lose a significant amount of its population to defections if its residents could get away with it. However, many North Koreans will likely attempt defections just to escape the brutal country. Many of its citizens have already defected to South Korea; like the math genius who just arrived in South Korea.
I wish the South Koreans would just storm across the border and take over the North. So many talented and innocent people in North are suffering under their crazy leader and that's insane in this day and age. I'm sure there are more prodigies in the North that the world will never get to meet.
People defect from North Korea to South Korea, not the other way around. As North Korea cannot escape the influx of technology, more and more people in North Korea will hear about how wonderful life is in other places. These people will do anything they have to for freedom, even if it means risking their lives.
With a leader that does not appear to have the best interests of North Koreans in mind, based on his erratic and dictatorial actions on a regular basis, why would someone want to stay in North Korea? The answer that I believe is gaining strength and popularity is defecting to South Korea. While still not perfect, it appears South Korea may be the safer bet of the two countries.