Paul - if it's the one I'm thinking of, we came down that trail beside Nevada Falls last year when we did the Panorama Trail, instead of going back from Nevada Falls to the John Muir trail. I felt very insecure on it despite the hiking pole - and not helped by the kids who kept overtaking us and were almost running down. We couldn't decide if their way was the foolishness of youth or if it was actually better to take it quicker. I think we did the same trail. You're right, it was much better suited for mountain goats than humans of any age.
Kids sometimes have no idea of the consequences of what they're doing.
If you fall on that trail you would just keep on falling and be severely hurt. It certainly wasn't the best trail for me at that time. I was really trying to be careful with my new hip, so my 19 yr old Son walked in front and on the real steep places I held onto his shoulder to make sure I kept my balance. We eventually made it down safely and was I glad. That was quite an experience for my first hike with my new hip.