I've read in other articles that the father was expecting a rope to be pre-anchored which makes me dubious of their level of preparedness.
> Typically, he said, there's a rope going through climbing carabiners that have been bolted into the rocks.
> "This time, the rope was gone," Whitson told CNN.
If you know there is a rappel: Bring. Your. Own. Gear. Trusting a rope that is left exposed and potentially not well cared for is dangerous in and of itself, but to be aware of a gear requirement and just walk out in the wilderness expecting gear to be there (and in usable condition) is flabbergasting.
I am glad this mistake wasn't fatal though.