Education centers in Xinjiang are described as providing 'aid and education' (帮教) which, as I discussed here chinalawtranslate.com/xj-education-c… is meant to address low level offenders, and be aimed at rehabilitation rather than punishment. It definitely should not be lengthy detention.
The recently amended XJ implementation rules for the Counter-terrorism Law (chinalawtranslate.com/%E6%96%B0%E7%9…) state that minor offenders who pose a real threat, but are repentant, can have punishment waived if they voluntarily accept 'aid and education' at education centers. (art. 39)
Given credible evidence of mass detainment and harsh conditions raised by @UN, media, and scholars; it is difficult to believe that participation in education centers is voluntarily. Of course, allowing independent experts to evaluate conditions would help resolve that question.
Agreement to 'education' in a center would only be truly voluntary if it was also 'knowing', meaning that the suspect fully understood the consequences agreement, and what other options were available to them (such as the max criminal penalty if they don't agree to 'education')
Whether XJ education centers are allowed under Chinese law is not the only question here. China can make its own law authorizing a new form of detention. Domestic 'legality' is the baseline, and a poor substitute for justice. Arbitrary detention is no sweeter by another name.
Aside: 双规, a form of Party discipline investigative detention, was also once justified to me as being 'voluntary'. I asked if people could leave it then, and was told of course not. It was 'voluntary' in that detainees had agreed to Party rules and waived rights when joining.
