Certainly not scientific, and perhaps of no better quality than my own anecdotes, but one can go to youtube and see just about every kind of behavior ranging from extreme safety, to clear cases of negligent behavior in regards to guns.
I suppose facts such as these make it easy to see that people are poeple, some are safe some not so much. In that sense we clearly know the question (if better stated) is relevant even if we have no easy answers.
This is also why so much emphasis is placed on safety in gun circles of larger groupings. We know people can be negligent, and creating a system of safety practices is our (the gun community's) reaction to those facts. (accidents are rare, but taking measures to minimize or reduce the incidence is rational)
Another anecdote: the company I work for had a very remote company headquarters located out in the woods miles from any homes and with an excellent backstop (a dirt ditch/ravine with ~40 foot from bottom to edge) and we asked the owner if we could make use of this to shoot at after hours, or on the weekends. At first the owner was VERY skeptical, in fact that may be an understatement, he is a gun owner and pro 2A rights and all that, but still a rational person wanting to protect the investment that is his business. So he called the sheriffs office made sure it was legal, but then still had reservations about safety. I had shot with him in the past, and he knew how strict I am with safety. So he allowed us to shoot with the stipulation that I handle safety, and that anyone that wanted to shoot had to be shown the ropes by me first. My point here is that the natural tendency for most self preservation types, which include liability concerns, is to overstate safety, and enforce rules that minimize risk.
I see this same behavior a LOT when it comes to new gun owners. They will keep the gun unloaded, locked in a drawer, or with a gun lock. Of course familiarity breeds contempt (if we accept that old adage as being relevant). Clearly training reinforces good behaviors, but I have no data as to how many gun owners actually get training, my gut says few.
My brother is an example of someone who probably should not carry a gun. I have a friend who openly admits his temper is such that he should never own a firearm.
On the flip side I think often its easy to think to yourself how stupid people seem when we see so much to criticize, however I think sometimes this is also a confirmation bias, stupid is noteworthy, average behavior is not, and a person who fails to create a noteworthy situation may indeed be a data point in favor of humanity, but we often only see the true failures of logic and reasoning becuase that is what is noteworthy.
anyways . .. I am rambling. lol.