Some of them have ancestors from N. Korea, dating back to 19th century. But they are not N. Koreans. There were there even before DPRK was born. If they are really N. Koreans, apparently Chinese authority is willing to take N. Korean refuges in large numbers. Then why does China send back N. Koreans escaping from N. Korea these days and turn blind eye to infiltration of N. Korean snatch squad who are roaming in ethnics Korean area to catch these "escapees" ? Again you are distoring the situation here.