Does anyone practice?
For any newbie, especially, I'd recommend some practice time on the stand before hunting. Get a partner and get it up the tree a mere four feet.
Learn just how much agility and balance you have. Learn how to operate the stand on a tree. Learn what has to be checked for tightness. Is your stand good for a twenty or twenty five foot climb up a tree. Is it good with you up the tree.
Most hunters fall because they are not tethered or tied to the tree.
If you're tied to the tree, you can't fall. But if you fall and are in safety harness, as Cossack noted, you don't have a lot of time. You either have to get on the ground or back in the stand/remaining stand. And for the latter, you better not be a couch potato. After a fall you need lower and upper body strength. It's not going to be like sitting in the TV couch again. I've strengthened my lower body by hiking every week and lifted small weights for the upper body weekly. Once I got to a certain age, it became a year round task for me, to get ready for hunting.
The problem isn't the safety harness. The problem is the newbie or old timer not ready for eventualities to happen with a tree stand. And without practice, many are not ready for serious events