The only ones I've ever seen on my boat have been caused by dive shops.
I do my own regs, as do a couple of my diving buddies. None of us have ever had a significant failure underwater as a consequence. I happen to believe that there's nobody who cares more than I do about having a working regulator down there, so I'm damn careful.
A friend of mine had a dive shop "overhaul" his regs and they didn't bother to check the LP hose sweges. Less than a month later he's on my boat, turns on the gas, and a LP hose explodes at the swege, which was conveniently behind a hose protector. Inspection of the pieces reveals that the hose was so badly checked that it should have NEVER passed inspection during that annual; there's no way that damage could have possibly occurred in less than a month. Of course, it was not actually inspected, was it? Me don't think so!
Had that happened underwater he might well have been good and screwed, as a blown LP hose is pretty close to the worst case scenario; it will reliably make the OTHER reg unbreathable as the IP in the remaining hoses will be so low as to be useless. (If you don't believe me try it sometime if you have a tank you want to waste on the exercise; just disconnect one of the regs and leave that LP hose open and see if you can breathe off the other one. Bet 'ya can't, or at least not very well, and bet the contents of the tank also disappear at a scary-fast rate!)
Actually, Doc, there's a good argument to be made that Magnuson-Moss and related laws already require the sort of thing you're talking about. I doubt very much that the impact was limited solely to the automotive industry, although the dive industry might try to argue otherwise.
What the dive industry lacks is a group of divers who are sufficiently enraged to engage counsel and make a (literal) federal case out of it, going after both the manufacturers and dive shops.
Hmmmmm.... maybe that needs to happen eh?