I am totally convinced. I've done some work on safety for national parks (Grand Canyon and Sequoia), including quite a bit of observation. It's insane what people do. I've seen completely unsupervised children climb delicate piñon trees beyond the guard wall at Grand Canyon. I have personally gone and found a ranger to deal with such situations, and I have watched other people go and get the ranger as well. I've seen people put 2 year olds on said guard wall (3 feet of sloping rock beyond it, with 400-1000 foot drops beyond that) and hold one little hand and teach them to walk atop the guard rail. This is something that I observed many times in one day (not always with a 2 year old, with various aged kids being allowed to balance on the wall). The parents enjoy it, take pictures, etc. One guy said (to his 18 month old) "This is a chasm, see the chasm?" (Mispronouncing the word - the mother hurried away and was not seen again that morning, the father sat his kid on the guard wall, went down to the part of the Canyon where there is no guard rail - I followed out of curiousity - and held one little hand as they approached deadly drop offs off trail - going off trail at GC is not recommended.
Kids are boisterous and run and play on rocks near rushing rivers (leading cause of death in Sequoia) and yep, the kids slip and fall. I got into this interest years ago when a law firm I worked for had a case where 2 scout masters lost a boy scout (aged 10) on an outing where they decided to cross a rushing creek in the coastal range on a log. They made it into a big challenge. Every boy but one managed to do it safely (on a wet log about 10 inches wide at the top)...except one, who fell and drowned.
People go beyond the railings at Moro Rock in Sequoia all the time, sometimes with kids. These are probably the same kids who return in their teens and manage to fall off.
Just yesterday, I watched a woman with 3 toddlers (all of them on those big wheel tricycles) cross the street near my house with her in front, not looking, as the babies peddled furiously to keep up and get to the other side (and up a driveway).