>> The young man was stupid enough to go to NK <<
Agreed.
>> and was stupid enough to steal a poster <<
Never proven. His “confession” was obviously under duress.
For all we know, moreover, he may never even have touched a poster, but rather was simply grabbed by the NORK’s to be used later as some kind of bargaining chip — or for some kind of propaganda stunt.
Possible, but the charge is totally believable. A trumped up charge would probably be more serious.
And since he was a student, I have to assume the parents were stupid enough to let him go, and likely paid for it!