Modern designs for things that can fail dangerously incorporate features that cause the system to go down a branch that ends in a safe failure mode high up the tree rather than allowing the possibility of a less safe failure many more steps down the tree.

It's like how Uhaul overbuilds the living crap out of it's trailers then puts relatively (compared to the rest of the system) light duty tires on them. Better to have idiots blow out tires than other less safe failure modes.