Yes, and there are also things called parents.
Having said that, it was a simple (less than 7 minute) hearing today, which can be educational for children.
I'm sure the judge will use his discretionary powers to limit age groups in future hearings, depending on the content.
im actually impressed with a 13yo taking true interest in the legal system. He wants to be a lawyer and wants to learn. I say let him, why block his intellectual curiosity? He seems pretty bright so far, so he would probably know how to watch the video if he wanted to..