Adventurous humans are peculiar. They like to push the limits, and seem have the best experience if they can get as close as possible to the danger point -- where going beyond might lead to a catastrophe.
And obviously, some people don't pull back from that limit soon enough, or they miscalculate, and something serious happens -- injury or death.
I think from the consensus here, nobody wants the government to stop us from having our adventures. Thank goodness too many lawsuits haven't occurred causing the government to "protect" everyone from having fun.
...and that brings to mind that other thread... Since Yosemite is now permitting people to climb the Half Dome cables, are they taking on the burden of ensuring that they are 100% safe? Are they ensuring that hiking the Mist Trail is safe? The area at the top of Vernal Falls? How about hiking the trail after dark? But since permits for the JMT have been in place for decades, I would think (or at least hope) permits for Half Dome would be just as safe from lawsuits.
Looking at those "danger zones" in Yosemite, if a private business were to conduct similar adventures on property they owned, the liability insurance would be so high we couldn't afford to hike, or there would be a ten-foot high fence along the Mist Trail and at Vernal Falls.
Unfortunately, in the case of Hot Creek, Inyo N.F. has put up that fence because someone declared it to be unsafe. It is a terrible shame, since the fence ruins the natural beauty of the area. And now, if they take the fence down, a lawyer friend tells me, that implies they have found it to be safe, so next time some idiot drinks too much and drowns there or gets burned wandering into the wrong place, they could lose a lawsuit.