Since I seem to have been the most vocal advocate on the forum regarding EDC of firearms, I will offer up my responses:
I have not shot anyone yet. I have not had the opportunity. I've been close to it, and I firmly believe that I would have no problem drawing down and shooting someone threatening me, my family or someone I felt was unjustifiably being threatened.
Up until a couple years ago, I carried a firearm with me every day. I was unable to carry a firearm on the Nuclear reservation, but did keep one with me coming and going. Since returning from Baghdad, I have not been able to carry a firearm with me as often as I would like, but now that I am in Florida that will change for the better. I've regularly packed a pistol with me since I was 21. I have a couple different carry rigs, one is an angle draw underarm shoulder holster, the other is a behind the back under the belt draw. I practice drawing from each position regularly, and feel confident I can deploy from either better than most. I prefer a 45, mine being a Glock 21, but also have packed a compact 40 S&W and my true blue Dan Wesson 357 4" revolver. I've also packed a Ruger Super Redhawk in a shoulder holster concealed, but this was not terribly practical, even given my large size.
While I am at home, if I am sleeping it is sitting on or in my nightstand. While I am at work, it may be in a drawer of my desk, or I may have it on me. I don't leave my guns in my car.
My oldest daughter is a certified hunter safety/education instructor, my younger daughter will be when she is 21 and becomes eligible. My wife is not as into it as the rest of us, but she knows how to take any of my firearms apart, put them back together again, load them, and shoot anyone that threatens her or her babies.
I strongly disagree with part of your last statement. I have never subscribed to the notion that children can't be left alone with or have easy access to a firearm, nor do I believe all firearms should be secured when not in use. These two statements are only true if the owner is not willing to do their part in educating and training their children how to behave in the presence of firearms, or leaves them out in plain sight. As far as irresponsible adults go, I've known plenty who had firearms that had no business with them, and never broke the law and gave no cause for anyone to try and separate them from their firearms. Irresponsibility is not a disqualifying criteria for denying somone the right to own or possess a firearm, unless the are proven legally to have that right denied (as in breaking the law).
I keep my hunting rifles and shotguns locked up because they serve no other real purpose, but self defense firearms are pointless if secured, eg locked up in a safe or with a gun trigger or chamber lock or some other disabling device installed.
As for facing a knife threat while armed with a gun, my advice is "don't bring a knife to a gunfight". Yes, you might be able to wound me if you get the jump on me, but I am pretty sure it won't be the wound of your choice, and once the Glock is out, then it will be my turn. You might get lucky, but is it going to be worth the risk, to take on a guy that is 6'6" and 260 lbs, and is already thinking about being accosted?
We just live in two different worlds I guess. I made some decisions long ago about how I would live my life and run my family, and it has worked out just fine for me and mine. It isn't the sort of life for everyone I am sure, but it suits me and the girls seem to feel the same.
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The ultimate result of shielding men from the effects of folly is to fill the world with fools.
-- Herbert Spencer, English Philosopher (1820-1903)