I saw this a couple days ago. From what I saw they were mainly just grappling. I honestly dont see it much different from adults doing it. It is a sport and it's safe. There are people monitoring the fight and they will step in if they need to. Its actually more safe than kids fighting in the backyard or on the school playground IMO. Not to mention, they have a very young start to what could turn out to be a good career. As long as they understand it is a sport and dont abuse their skills in normal everyday situations, I see no problem with it.