*The Chinese don't catch a lot of grief for their "Islamophobia," but this list, from a human rights campaigner, is pretty comprehensive. Obviously the Chinese secret police don't need "reasons" to disappear people they don't like; they'll even disappear movie stars like Fan BingBing if they're in the mood. It's not about the rule of law or justifying their actions to the arrested, it's demonstrative of a comprehensive attitude of social constraint, a kind of Tao of anti-terrorism.
Things which may cause you to detained without trial and locked away in an education camp indefinitely, in Xinjiang, China, 2018:
Owning a tent
Owning welding equipment
Owning extra food
Owning a compass
Owning multiple knives
Abstaining from alcohol
Abstaining from cigarettes
Wailing, publicly grieving, or otherwise acting sad when your parents die
Performing a traditional funeral
Inviting more than 5 people to your house without registering with the police department
Wearing a scarf in the presence of the PRC flag
Wearing a hijab (if you are under 45)
Going to a mosque
Praying
Fasting
Listening to a religious lecture
Telling others not to swear
Telling others not to sin
Eating breakfast before the sun comes up
Arguing with an official
Sending a petition that complains about local officials
Not allowing officials to sleep in your bed, eat your food, and live in your house
Not having your government ID on your person
Not letting officials take your DNA
Not letting officials scan your irises
Not letting officials download everything you have on your phone
Not making voice recordings to give to officials
Speaking your mother language in school
Speaking your mother language in government work groups
Speaking with someone abroad (with skype, etc.)
Speaking with someone who has traveled abroad
Having traveled abroad yourself
Merely knowing someone who has traveled abroad
Publicly stating that China is inferior to some other country
Having too many children
Having a VPN
Having Whatsapp
Watching a video filmed abroad
Wearing a shirt with Arabic lettered writing on it
Wearing a full beard
Wearing any clothes with religious iconography
Not attending mandatory propaganda classes
Not attending mandatory flag raising ceremonies
Not attending public struggle sessions (Cultural Revolution style)
Refusing to denounce your family members in these public struggle sessions
Being related to anyone who has done any of the above
Trying to kill yourself when detained by the police
Trying to kill yourself when in the education camps proper.
Something terrible is happening in Xinjiang.
