Ok I will admit I had a complete and total brain and forgot about the 1911 grip safety. So remove all the guns with the grip safeties (still relying on a mechanical piece to insure your safety) any other gun not just Glock can AD.
I was also sitting here thinking. If you are holstering the gun more than likely your hand is going to be on the grip. With your hand on the grip you are pressing the grip safety in and the AD could still happen. I did it with my XD all the time. Of course i know a guy who still has a gen 1 glock he has been carrying for God only knows how long, and several other people who carry a Glock on an everyday basis. No accidental disacharges around here.