I was shocked than anyone could leave a young child alone at a concert or anywhere really. I guess they did give him a phone so maybe they thought that was ok.
I commented to Jon that I was surprised they had left him. I felt that although they didn't ask me to watch him, it became my responsibility to look out for him. What if there had been an evacuation, or what if I had wanted to go out for a smoke or to the bar for a drink. There is no way I could have left him, how could his "carers?!"?
I couldn't even have left my nearly 10 year old in a situation like that. Now maybe I am being overly paranoid but I don't think so, or maybe he was just a very small 16 year old!