Intersting isn't it that the 1911 does not leave the grip safety to human error. It pretty much requires a hand in it.
You are either depressing it, or you are not. The chances of an accident involvolving the depressing of the trigger AND the grip safety, at the same time, are more remote then merely some cause, human, or otherwise, just depressing the trigger.
Glock has a number of safety features built in, one of which is the protrusion on the trigger that acts as a safety.
Glock says this is a safety. Not me. OK?
How about the odds of accidentally depressing the 1911's grip safety, AND the trigger, AND accidentally pushing off the safety, all at the same time?
A Glock is NOT like a revolver, unless it has the 11 pound cop trigger. A standardd trigger Glock is closer to a cocked 1911, with no grip safety, and no manual safety.
For perfect, error free shooters, such a safety-free 1911 would also be perfectly safe.