Well there *was* a time in the US when arms were common enough that you grew up in a culture that pretty much integrated safety into the commonplace aspect. I suspect, if you go back a few years, that the UK enjoyed such a period, at least regionally.
Of course, you're always going to have idiots. I grew up with several. Never had one die from firearms. Had several die from cars + booze, a few from drugs, a couple from sporting accidents. We still kill more people with cars, even with lots of training and practice and licensing. You can't legislate common sense, and when you breed it out of the culture you're going to have increasing amounts of entertaining fail.
BTW, I don't reckon she "shot herself" using any kind of actual firearm, as the muzzle velocities, even from a .22 pistol, aren't going to leave the round in a wound shallow enough for you to pluck the bullet out yourself before going to hospital.
Failing to account for all the rounds . . . ? Easy enough with .22 cartridges if they're "bulk packed" loose in counts of 200 or more. Most of mine are in bulk packs of 400-500, so it would be quite possible to spill a handful and never know if you'd recovered them all.
However, just wadding up a sheet of newspaper that had been under the rounds? Without at least a cursory check first? . . . That's not terribly prudent. I mean, if she had leaned in to apply a poker to the fire, and the "shallow wound" had been on either side of her nose . . .
Very different story.