I fully concur there is no such thing as an AD, plainly and simply, someone done something stupid! I speak from a personal experience of being stupid, but since that incident I have become overly cautious with a firearm, and all are loaded until I have personally checked to ensure they are are not, I TAKE NO ONES WORD FOR IT!
Back in the mid-sixties, while in the Air Force, I earned a spot on the base pistol team. We were each issued two .45s and a .22, we also had an unlimited supply of ammo, which I took advantage of. I had been to the range and had taken a couple of personal revolvers with me for practice. When the practice was finished I checked the guns, put them in the pistol box and went home to get ready for a party that night. When I arrived home I went into the bedroom to put the pistol box in a closet, I remembered my personal guns were in the box so i opened it and removed them. I placed the .22 on the shelve in the closet, in doing so I noticed one of our kid's toys in the hallway just outside the bedroom door. I aimed the .357 at the toy and pulled the trigger..........bang, the gun was loaded. The bullet struck the floor in the hallway, ricocheted and hit the base of a commode in the bathroom across the hall, it exploded into a million pieces. I had water running everywhere until I could get the valve turned off, and then a hell of a mess to clean up. At that time we only had one bathroom, it was near 6 PM on a Saturday, and at that time nothing was open on Sundays. I am luck I had a five gallon bucket and some plastic bags.
This act of stupidity almost cost more than I was will to pay, when I fired the gun my 4 year old son was in the hallway playing with the toy, I couldn't see him at the time, but he was less than four feet away. Today, with the exception of my carry gun which is always loaded, I check each gun at the range or in the field before going home, and I check them again before taking them in the house.