This is a form of peaceful protest against the abusive handling of a boy who took an electronics project to school. The project was simply a digital clock and law enforcement decided to arrest and hand cuff the boy because it 'may' have looked like a bomb to some people.
In the country where I live - if a parent were to hand cuff a child then this action would be considered 'child abuse' by authorities and the child would be removed from the parents for the child's protection.
I seriously think we need to consider removing children from some authorities to protect the child! Perhaps we need better training for law enforcement on appropriate behaviour towards children and/or specialist officers to work with children.
In any case - the hand cuffing of an innocent kids is NOT OK!