Parents who let young children operate motor vehicles like this should be prosecuted to make examples of their negligence!!
My kids have ridden motorcycles since they where about 8 and 9 yrs old. Bumps and bruises are all part of a physical, demanding sport. The only time my son has gotten hurt badly enough to go to the ER was when he was collieded head-on with another motorcycle, ridden by a guy in 20s, who was barefooted, wearing no helmet, and probably drunk. My son was in an small area with other kids his age, riding in a clockwise circle, and this guy came in recklessly full speed from a blind area. My son clearly tried to avoid the impact; the other guy didn't know what happened. I was there within 60 seconds, and carried him back to his horrified mom. He rides with good safety gear, which absorbed most of the force, but his leg was cut through the body armor, and the only place he refused to wear padding (!!) was his arm, and his elbow was fractured.
Just like anything else in life, this equipment is only as safe as the people who operate it. My son could get killed riding his bicycle if he was operating it in a foolish manner.
If I had a farm or other property, my son and daughter have earned my trust, and I'd let them ride on our property. They wouldn't ride on public streets.
My son has been shooting rifles and pistols since he was about 5 yrs old. "BB" guns at first, and later real weapons. (He ended up defending the 2nd amendment against his leftist, anti-gun teacher when he was in the fifth grade, by grabbing a copy of the constitution from the classroom library, but that's another story.) It's all part of the same argument. Lots of folks think that parents like me who introduce firearms, motor vehicles, and so forth to young kids are irresponsible. However, I think that there are a larger number of parents who won't spend time with their kids, won't communicate with them the risks, dangers, and responsibilities that go along with becoming adults, and who fail to teach them safety.
Blame these parents for not supervising their kids, if you feel you have enough information about them from these news reports, but don't blame all parents who SAFELY teach their kids how to grow into adulthood, how to accept adult responsibility and accountability, using such "toys", tools, and weapons as one means to that training.
Most of all, I grieve for these parents horrible loss. My daughter is now a 14 year old sophomore cheerleader, and member of a renowned school choir. That's two activities that take her from her dad's control, and it scares me to death. She'll be singing in Russia next year (...oh boy), she's running all over to different school games (mostly with adult supervision, but occasionally, and unavoidably with younger adults or teenagers driving, and that scares me more than seeing her on a jet-ski or motorcycle. Both of my kids (now 14 and 16) have cell phones, and we keep tabs on them like they were still 5 (or so my daughter claims).
God Bless these families, with peace, and the eternal comfort only He can give.
SFS