I saw an Iranian man in Ankara who were rejected for Green Card Lottery visa because he had a trip to North Korea (Iranians can go there without a visa). In a private talk he admitted that he was working for army and he was educated for missile stuff in N. Korea. My point is, if he never went to N.Korea, he could have make it to the US. Someone who worked for Iranian Missile Program. FBI background check is not accurate.
I was sent back to North Korea three times and finally I escaped to South Korea. I was lucky because I got a scholarship from a organization, so I was able to come to the US to study English. The first time I went to China, I thought they were really rich because they ate rice and meat everyday. It was the same as I heard when I was in North Korea.
Edit:
She also mentions an organization called "Liberty in North Korea", which helps refugees to escape via China. China has an agreement with North Korea to send illegal immigrants back to their home country. Apparently, if you know the right people and pay some money, you can circumvent this agreement: [1] lists "rescue fees" as "Costs for fines, fees, and the network of partners and staff in the underground to bring refugees to safety".
[0] http://interviews.kinja.com/how-did-you-end-up-making-it-to-...
update: this was a general comment, not specific to this article where the writer might need to protect her family and thus have good reason not to go into details.
This law: http://en.wikipedia.org/wiki/North_Korean_Human_Rights_Act_o... offers details on how the US treats North Korean refugee's and should provide a springboard for more research.