Hmm...
I wasn't aware that posting a simple thread about my son showing great interest in Diving at an older age would start a war. But since it has...I will toss in my two cents.
I come from a family that learns to swim at a VERY young age. In fact my son at 4 years old is about the oldest anyone of my immediate family learned to swim. That is my fault as I work a ton of hours and haven't spent that much time with him in the Pool.
We as children also learn basic survival skills, and hunting skills early. We typically are shooting at the age of 10. I remember being 8, 9 , and 10 with Blow Guns, Tomahawks, Throwing Stars, and Small Crossbows to name a few. All used under absolute adult supervision, zero injury ever! Some people can scream "Your parents are nuts!" all they want, but I have wonderful parents that allowed us to experience many things as children, and we were never injured. We learned safety, and respect for those items.
Now had my parents simply said "Here ya go!", like some parents would do, it would have been ugly and people would have been hurt.
So when my child is 10, and if he shows the ABILITY and UNDERSTANDING to dive, he will. Obviously starting with snorkeling, and free diving, going forward from there. Why should I hold him back? As for the comment about insurance, trust me..my family is more then covered if I were to be hurt, or anyone else in my family.
All in all I come from a family that is huge into the outdoors, and has always allowed the children to explore their own abilities, in a safe and structured environment. I guess another way of looking at it is that driving down the road with your children in the car is a lot more dangerous then letting them try new things in a controlled structured environment. You aren't in a controlled environment when driving...
People need to relax a little.