If my child were the victim I most definitely would step in! I'd explain to the misbehaving child what they were doing wrong and why they should stop and then stay with the child until their parent arrived. But if I didn't know either party involved, unless the child was in immediate danger, I would mind my own business.
What do you want the panelists to weigh in on? Email your ideas to editor Tamara O'Shaughnessy at firstname.lastname@example.org.