Some discussion in our school this week about this. The issue is a small handful of very disruptive students who seem to be running the school. Attempts to impose sanctions fail time after time because parents come in and take the side of the child. SMT tend to cave in and the classroom teacher is left with the continued disruption. If we had evidence that could be shown to the parents and SMT it would give us some support. However, it also raises some big ethical questions. Apparently two schools in the UK have already trialled the use of bodycams.