First of all, Glocks are safe, its the damn bullet thats dangerous. I know people rant about keeping your finger off the trigger, but in an adrenaline charged situation trigger pressure tends to be more than perceived and you get accidental shootings. That is why some PD's tend to like DAO pistols, the 1911 is just as dangerous with the safety off and the gun in hand.
In a gunfight most people aren't thinking, is my finger off the trigger until I get out of the holster, thats why most PD's have extensive training programs with these pistols. That is where the citizen is at a disadvantage, they don't always have the resources for ammo and don't get the training. Like driving a car, usually training ones self is by trial and error, and error can hurt.
I feel owning and using a Glock requires a bit more focus than some other pistols. Lack of focus shouldn't be an excuse as with ANY gun TOTAL focus should be utilized, but thats in a perfect world.
The only safety issue I have is chamber support on the 40 cal Glocks. I have seen way too many once fired factory empties on the police range that had a large bell at the web and were way past spec for reloading. Even using the push through die I do not trust brass thats been stressed that much, it has to suffer from fatigue more than normal.