The watch towers, double-locked doors and video surveillance in the Chinese camps are there "to prevent escapes".
Uighurs and other minorities held inside are scored on how well they speak the dominant Mandarin language and follow strict rules on everything down to bathing and using the toilet, scores that determine if they can leave.
"Manner education" is mandatory, but "vocational skills improvement" is offered only after a year in the camps.
Voluntary job training is the reason the Chinese government has given for detaining more than a million ethnic minorities, most of them Muslims.