It happened to me also at the Grand Canyon back in 2000. I underestimated the challenge of hiking from Rim to River and back with a nine, and twelve year old. It did not look so difficult, we even took the easier route. No supplies just a couple of bottles of gator aide, no over night permit ( who needed that?!), a credit card and drivers license. Humans are very bad at judging risk. I have gotten better since then, now I just limit the risk to myself. Great article.