Spicy topic, @
Glenn E. Meyer. I'm not sure this belongs in the competition subform but let's see how the discussion evolves.
See BBI's
excellent sticky post on why good guys lose. Safeties are one reason.
At matches and in training I've seen more issues with grip safeties than with thumb safeties, but enough of both to convince me that I don't want either on a defensive handgun. These have included: 1) Failure to deactivate safety before trying to shoot or clear malfunctions, 2) failure to activate safety before holstering, and 3) broken safety.
Who have been the worst safety offenders? Obviously, I don't have stats but far and away
kids are #1 on not using safeties correctly. New female shooters have been a close #2. Grip safeties are the most common with kids and newbie females--probably because of hand size. But thumb safeties are constantly not being taken off, and even worse not being put on prior to holstering.
I don't think advanced age has much to do with it. It's lack of experience, stress, and/or cognitive load combined with something unusual that seem to be the main causes.
I've guided my family members toward Glocks with SCDs, even though I almost always carry a TDA w/decocker only. Remembering to decock before holstering presents a similar issue to a safety. I've forgotten to decock and thumb-check exactly once in my life, and you can take that as a good or a bad thing--or both.