Why bother with a one time strike? Does terrorists get a one time strike? Screw those rioters, anyone get caught will get a permanent relocation to a labor camp. If the person is underage, the parents also get that free trip. Only way to get reduced sentence is to rat out someone the police don't already have. If the person is in a position of influence such as teacher or religious person, get double the penalty.China should introduce new laws to deal with the rioters’ use of child soldiers.
You have a one strike policy.
First time a minor is arrested for rioting, they are released to their parents. The parents need to be made explicitly clear, and sign a document stating that they understand that if they child is so much as caught littering, they will loose custody of all their children and be charged with child endangerment.
If these parents cannot educate their children on things as basic as not rioting, then they cannot be trusted with those children.
Similar laws need to apply to teachers and religious leaders. If children under their care end up involved in rioting, they get put on the same register as sex offenders, are barred from ever working with minors, and cannot to within 500m of a school, playground or other area where young children are likely to congregate.