The younger generation regularly mocks the Kim regime and its politics.
Offered bribes are no longer a steady source of supplemental income.
The lecturer is the third American held by Pyongyang amid rising tensions with Washington.
Seven members of three families take guards' guns, throw magazines in Tumen River before fleeing on April 15.
Defense attorneys accuse police of holding back vital evidence after letting North Korean suspects go home.
The move follows other measures taken to show Beijng's anger over a security move targeting North Korea's weapons program.
Sources say customs officials are hunting for illicit cash smuggled in North Korean trucks.
They are heard saying that money spent on weapons tests would be better used for civilian needs.
Authorities believe the gadgets will prevent guards from crossing the border to commit crimes, sleeping on the job, and assisting defectors.
Citizens’ lives were on the line in dispute around Kim Jong Nam’s murder, they say.
Censorship and steep fees deter them, despite the impact on their business.