Quite often when ever a gun goes bang when the person holding it did not want it to or that person shoots at a target they did not properly identify the word "accident" is often tossed out as the reason the gun went bang or hit the wrong target. Most of the time, after I have heard or read what I think are the known facts I think "negligent" better describes what happened.
To my way of thinking if at any time we fire a gun because our finger was on the trigger it is not an 'accident", whether we meant for the gun to go bang then does not matter as we intentionally put our finger on the trigger. If at any time we shoot the gun and the "target" turns out to be some thing other then what we thought we were aiming at it is not an "accident", since we deliberately aimed and fired the gun. This is different then a proven mechanical failure of a firearm.
My Dad, my Uncle Ed and me were pheasant hunting in November about 55 years ago and the single barrel 20 ga. shot gun I was carrying had an exposed hammer. I was cold, wearing gloves, 10 years old, and "negligent". A pheasant took off running in front of us and I cocked the hammer and when it flew one of them shot the pheasant so I lowered the hammer. When I held the hammer with my gloved thumb and pressed he trigger to lower it the hammer got away from me and the loudest noise I ever heard happened. I blew a hole in the ground about 3 feet in front of me and Dad and Uncle Ed were not impressed, I can still see their faces. Dad took all my 20 ga. ammo and I carried an empty gun the rest of the day. He later explained to me again that I should of removed my gloves when I wanted to lower the hammer, some thing he had said before.
I think the media tosses the term "accidental" out there because they don't know any better. Then again if a tragedy occurs and a family is grieving, the only ones debating the term are the D.A and other lawyers.
For me it comes down to responsibility and ownership. It is my responsibility to make sure the gun goes bang only when I intend it to, and I "own" the bullet when it leaves the barrel.