This is a news account of a recent fatality within Grand Canyon. I believe we were discussing how to hike in the heat (or not) just recently.
Grand Canyon National Park has a very active and proficient Search and Rescue operation, but outside help can only do so much individual actions and decisions can avert tragedies like this and render outside assistance unnecessary.
Of course, Federal legislation should be enacted, making dying within a National Park a severe criminal offense, with appropriate penalties....
We are heading to one of those less visited NP in September, North Cascades (five days/four nights backpacking and four days of day hiking). A National Park that is still a park, where during months were school is in session you can't even make reservations at the campgrounds. We are looking forward to a lack of crowds.
Next time we go back to Grand Canyon, and I'm sure there will be a next time, we are already planning on hitting the less traveled trails. We were talking to a ranger about them while there, mainly about the availability of water. After our first visit in 2012, we said we were going to go back and do rim-to-rim and this is the year we were finally able to make it happen.
Next year is Grand Tetons, our trip from last year that got COVID cancelled and one or two other lesser traveled but still beautiful parks. Gates of the Arctic is high up on my list, though I might have to find someone else to go with. Denali too.
At the GC they post signs along the trail featuring cautionary tales of dead hikers. They are mainly aimed at people who think it's a good idea to run from rim to rim in a single day (it's not). It probably just encourages people to think they are tougher than the ones who died.
That said, there are actually remarkably few fatalities at National Parks with drowning, vehicle collisions and falls the main causes of unintentional death: https://www.nps.gov/orgs/1336/data.htm
Having run from the north rim to the south rim in well under 8 hours, I would say it is fine if you know what lies ahead (and down!). The route we followed was over the Black Bridge, just wee bit short of a standard marathon (we all had marathon experience and self contained medical support). I was surprised at how good I felt that evening at dinner.
It was great experience, but I would not recommend it for a first visit to GC. There is so much more there that can be savored at a gentler pace. GC is full of hidden delights.