Is it illegal for China businessmen to exchange goods with North Koreans at the border?

1, do you think the American military police are awesome or the China military police are awesome? The best American military police in the world can't stop Mexican illegal immigrants, let alone the military police in China. 2. The defectors didn't run for their lives alone, but the South Korean government helped them escape. When they sneaked into China by various means, the Korean Embassy and Consulate quietly provided assistance, providing various means of transportation and diplomatic cover. 3. So far, North Korean defectors have not caused waves in China, and terrorists from other regions have not caused waves in China, which shows that Turkish military and police still have laws to follow.