They have some Chinese coming in for novelty tour. I heard some of them have warm and fuzzy feeling about themselves light years ahead of NK. It makes them feel like bragging and looking down upon "stupid" N. Koreans. Then there are some ethnic Koreans from other countries such as U.S., Canada and Europe. Some have family connections. Others are pro-North Korean agents or agents of influence, parroting NK propaganda in their home countries. NK cultivated overseas network in ethnic Korean communities all over the world. There are some in U.S., too. Last I hear, they are on FBI's watch list.
Then there are out-and-out novelty seeking expat drifters, and those whose curiosity beat their better judgement.