A big problem with any weapon is reholstering. People snag the trigger on threads, twigs, keys, and fingers while reholstering with a resulting negligent discharge. I personally always take my sweet time reholstering any of my weapons, mechanical safety or not.
And don't get me going on the Glock clip! (Anybody who puts THAT on their Glock then stuffs it unholstered in their pants is begging for trouble.)