So what are they up to?
Chain restaurants, 'natch:
Kim Myung-ho, a North Korean defector who ran a restaurant in northern China, reported in 2007 that each establishment, affiliated with "trading companies" operated by the government, was required to meet a fixed benchmark payment. "Every year, the sum total is counted at the business headquarters in Pyongyang, but if there's even a small default or lack of results, then the threat of evacuation is given," Kim told the Daily NK, a North Korea-focused online publication. Evacuation -- going back to North Korea -- is a serious threat for someone who is allowed a few years in the relative prosperity of, say, Cambodia.
Sort of explains why Kim Jong-Il decided to lay claim to the invention of the hamburger.