I had an AD in my home late last year with a 9mm carbine. It went through the floor of my room, through a heating duct, the ceiling of the room below and lodged in a wall stud in the room below mine. Fortunately I was the only one home at the time, but as a result, I personally do not keep loaded mags in the firearm. They may be with the firearm in the case, but in a seperate pocket.
My dad keeps his pistol with a loaded mag, empty chamber. Thats how i caused my AD, so I dont do it anymore.