Accidents can always happen. Be it on the baseball field, football field, jumping on a trampoline or even hiking through the woods. But, when we consider the various aspects of hunting safety, especially deer hunting and the use of ATV's, maybe there should be a small section of the hunter safety course that addresses ATV's and their use. It wouldn't probably address adult safety, but maybe it would make those who are soon to become young adults in the future consider who to keep their kids from serious injury, especially when they are very young.
http://www.wthr.com/story/22663366/2013/06/23/atv-accident-3-year-old-riding-with-4-year-old

Why would anyone allow a 4 year old to operate an ATV to begin with? On top of that, why would anyone allow a 4 year old to carry a passenger on that ATV?

Finally....if you are going to allow children to operate an ATV...why wasn't either child wearing any safety equipment (or @ the very least...a helmet)?

You cant legislate common sense.