Your child is in a sport, lined up for an activity. The kid behind your child is touching them. ( Kicking, tickling, grabbing etc.. you get the point lol ). Your child is asking them to stop, but isn't visibly upset or anything. Their coach or instructor ( whoever is in charge of said sport ) does not notice. This isn't the first time this has happened either.
So what would you do? Would you tell the person incharge in private about the situation? Or just forget about it? Or...???