This movie is basically a documentary made into a commercial movie. The production crew had access to declassified police files, and were told by the police to not write too much on how police solving the crime so that the criminals won't improve their countersurveillance.
The purpose of this movie is to remind people to stay away from scams. If you've received many spam calls, they most likely were called from these camps.
It's no secret that these camps are majorly running by Chinese along the Myanmar border near China, Thailand, and Laos. There are videos and news about Vietnamese escaped and Philipinos rescued.
Based on the Chinese news, part of Chinese people went there voluntarily just like in the movie, but many were fooled by foreign jobs ads with high salary, team building travels, and kidnapped while traveling there.
Is it also to consider that Myanmar is having a civil war. The northern Myanmar is in Anarchy state, and some other areas are shared authorities among warlords and Myanmar government. Warlords and government officials who are not limited in Myanmar benefit from the profits made in these camps.
Good news is that China, Thailand, Myanmar, and Laos have made joint taskforce to raid these camps and save the victims.
There are many interviews on those who escaped if you care to watch. This movie managed to keep things at bordeline humanitarian level for the audience, but should be rated as PG18.