Great minds think alike!
I had been thinking of exactly that, pigboat! When I got going in civil aviation about 40 years ago, it was the Bonanza that used to wipe out those guys with enough money to buy one but not enough patience, or respect for the Laws of Gravity, to learn to fly one properly. It must have been the exact equivalent of these modern turbo-props.
I will never forget looking at the wreckage of a Bonanza that some, yes, doctor had been flying when he lost it on instruments, spiralling in and then pulling its wings off. Aside from the engine and prop, and the wheels, the largest piece of that airplane that you could recognize as such was the baggage compartment door, still nice and shiny. The rest was just mangled junk
I remember, too, one fellow who told me in all seriousness that he depended on his autopilot for flight in IMC in his new Cessna 182, that, yes, he knew his basic instrument flying skills were not very good, but he knew how to input commands to the autopilot that should keep his airplane under control for him.
Man, that's like dangling from one silken thread over an abyss, isn't it? But that guy had a lot more money than I did (some guy working at Burger King had a little more money than I did), so that he wasn't very interested in whatever some scrawny CFII had to tell him. In fact, I think he thought I only wanted to sell him some flight instruction, to teach him some skills he probably would never need.
I was looking again at the operating manual PDF that Con-pilot linked to. There's a check of oxygen quantity and shut-off valve position on the pre-flight walk-around, and there's a check that the mask flows in the pre-start checks.
A friend told me about a King Air that turned itself into a burned-out wreck from an oxygen leak, left parked, so that some operators must shut the valve to the oxygen bottle when they finish flying for the day. It must be easy to miss opening that valve again when you next go flying, particularly if you don't check that the mask is flowing.