Severe collapse of the middle class of North Korea who is engaged in trade of illegal books and media.

Severe collapse of the middle class of North Korea who is engaged in trade of illegal books and media.
In North Korea a lot of people earn money from illegal trade of books and videos from South Korea.
Recently North Korean government began to monitor to catch illegal traders of books and videos from South Korea.

I think North Korean government is afraid of the cultural influence from South Korea.
Sometimes cultures are stronger than weapons.

http://www.rfa.org/korean/weekly_program/nk_now/fe-ms-08012016101540.html