Although slightly off topic, I saw an incident a couple of years ago at King's Canyon. We were doing the walk around the top, and at one place where there is a sheer drop of hundreds of meters to the bottom, a kid about 8 or 9 ran towards the edge, stopped about a meter from the edge, and hurled a big rock over the side. I nearly crapped, I thought he was going over the edge. The mother (I presume it was his mother, and no male partner visible) didn't even bat an eyelid. Luckily another person, who didn't appear to be with them, ripped into her and told her irresponsible it was, and etc. etc. etc. I was still speechless, I honestly thought he was a gonner, and if he had tripped he would have been. Not only the danger to the kid, but also there are people walking around the bottom of the cliffs too.