I think you must mean the average gun owner, but I'm not sure. My guess it that all members of the S&W forum are gun owners, and do not stick their guns in sock drawers. I'm not referring to them, I'm referring to LEOs and perhaps soldiers and experienced gun owners that take firearms seriously. I've seen soldiers, NCO's and officers commit negligent discharges with a variety of weapons. These are (supposed) experienced, trained personnel. They were negligent; it was not the fault of the weapon in any way shape or form.
The Glock is a simple weapon, it's an easy concept with a Glock. You pull the trigger it fires, just like a revolver. No complicated safety switches or levers. If you clear it correctly, like you have been trained, it will not fire. I will make no opinionated comment about an organization that allows negligent discharges and then blames them on the weapon, I think it's pretty obvious what's wrong with that. People have preferences of what weapon they use, or, if they belong to an organization that issues a weapon, they recieve training and they become proficient with it, or not. In the military, where you use what you are issued whether you like it or not (and do not ever have an option of personally owned weapons), we punished soldiers that failed in that area, particularly in combat zones. The reason? That's how you kill innocent people, to include your peers. Unless the weapon malfunctions (which is rare), you cannot blame it on the weapon. By punishing those that commit such acts, you send the message to the sock drawer crowd to pay attention.
One of the amazing thing about Glocks are the amount of quality they possess vs. the price, it's no wonder an organization chooses them. I carried one in Iraq and found it to be the equal to the P 228 that I owned and wished I could have carried while there. I think it's superior to the issue M9, equal at worst. The M9 is subject to lots of negligent discharges, but no one in the Army suggests it's the fault of the weapon or it's design. I would have to see the actual case event of a negligent discharge with the Glock before I would believe that it has anything to do with it's design. The clearing procedures are the same. The Glock is not a complicated weapon, in fact, it is simpler than the SIG (at least the one I own). Complacency, and irresponsibilty are the only reasons for negligent discharges, there are no allowable "reasons". I would like to hear why the design of the Glock "causes" more negligent discharges than other weapons of similar type. "Operator headspace and timing" is the phrase we used to use to explain such phenomena. We also used to say "the maximum effective range of an excuse is 0 meters". Silly little slang terms, but actually pretty close to truth. S&W and SIG would love for you to believe that Glock makes unsafe weapons, just like Ford would love for you to think Chevrolet makes unsafe automobiles.
I have never had a negligent discharge with weapon, and I have fired, qualifed and used a lot of different systems in a lot of different environments. The only people I ever saw have negligent discharges were what I considered to be substandard members of my organization, I never saw what I considered to be a professional soldier commit such an act. Maybe those who have had negligent discharges are not the ones to listen to on how not to have them, no matter what the weapon type.