I wish I had something meaningful to contribute here but I really don't so I'll just ramble for a minute. Feel free to skip to the next post if that idea doesn't appeal to you.
I started carrying appendix part time in the late 90's with a G26 and then a G19. I didn't know anyone else who also carried aiwb back then so I never realized how dangerous it was. I'm amazed I didn't bleed out long ago. When I say I didn't know anyone else carrying aiwb, I mean competent folks who I associated with. Only about 20,000 NY cops were also carrying aiwb at the time, either off duty or on duty (as a backup weapon position, aiwb was pretty popular then in NY. No idea if it still is) Also, aiwb was probably the very first carry position when pistols were invented, so its not like its new or anything. None of us invented or popularized aiwb. I have mostly carried aiwb ever since, though I did take a break for a few years for reasons that may not be worth getting into now, but mostly involved not wanting to switch holster positions any more than I had to. On that note, I have seen plenty of people reach for guns that weren't where they thought they would be, both under timed stress and in FoF. As someone else already mentioned, you mostly see it with magazines, and I have seen everything from knives to batons to flashlights to cell phones get shoved into a pistol grip in the hopes that they would spit bullets. There are different reasons why that happens, and not all of them are relevant to this ramble but sometimes people do that when they expect a mag to be there and find something else instead. I'm reasonably certain that aspect also applies to other items besides mags.
On another note, all the references in the world to "top shooters" is really starting to wear me out. If "they" could be stereotyped, the most common thing would be that they all do different things for different reasons and you shouldn't draw too many conclusions from what they do. I've been guilty of it in the past as well. Having more than my share of actual top shooters as friends and training partners over the years, (not just guys who look good in practice, but guys who actually perform year after year.) have to say that many (most?) of them are not as safe as I strive to be, and all of them do things to improve what matters TO THEM. What matters to them rarely matters to me. Carrying a gun concealed 16-20 hours a day in case they feel the need to meet the grand jury is not high on their list and frankly, almost none of them understand it well at all.
As for safety issues while carrying and training aiwb - I don't believe that aiwb is any more likely to result in an ND than any other position, IF THE SHOOTER DOES WHAT HE CAN TO MINIMIZE ACCIDENTS! A good list of things to do has already been posted before and I'll not rehash it now. If the shooter does what he can, and an ND still occurs, I don't think death is likely to result. My gun very rarely points at me, and as long as I don't forget all of my 9,000 hours of training, I am pretty unlikely to shoot myself. What some competition shooter thinks about the issue is moot to me. I have a lot of real world draws from aiwb, and have a pretty good idea of how I will react under stress (if past performance is any indicator). Having said that, all of us are human and none of us are too high speed to fail. Which is why I have multiple redundant safety procedures built in to my gun handling. I know several top shooters who have not only had ND's, but also shot themselves. I'm trying very hard not to join them.
Along those lines, I usually assume that people on PF are serious, squared away shooters who know what they are doing and why. Unfortunately, this isn't always true. I have met many guys in my time on the range who talk a good game, and who can even produce good results some of the time. Unfortunately, lots of people still lack the fundamentals. Even among the guys who shoot a lot and like to train, practicing the basics is not that sexy so they don't do it, or they don't do it well enough and deep enough to get serious long term results. A good measure of how well someone understands and can execute the basics is what they can do cold. Warmed up really doesn't interest me at all. Even in big competitions, there is often so much time between stages that no one really gets to warm up effectively. That tends to sort the actual experts from the "training range" experts. Watching how people train will also clue you in to this stuff. There may be more than one way to skin the cat, but there sure are even more ways to fail.
Anyway, I'm sure I left some stuff out, and I'm not trying to step on anyone's toes or single anyone out. If you think aiwb is too dangerous, don't use it. We're all adults, we all need to make our own decisions. Personally, I still rank driving as way more dangerous than aiwb.