There is only two possible ways a Glock can fire if the trigger isn't deliberately pulled. One is if the trigger moves to the rear when dropped (just like being pulled), and the other is if the sear engagement is so little that jarring the gun makes the trigger slip off the striker and the trigger bar is far enough back to depress the FPS. The gun can only fire if the FPS is depressed. Period.
Lots of times the gun will drop the Striker from the cocked position when dropped, but the FPS doesn't allow it to go forward thru the bolt face, so the safety did it's job.
If the ZEV Trigger bars had the cam for the FPS so far back that they allowed this to happen then they should have been recalled, or more to the point, they should never have gone out the door in the first place.
I got over aftermarket parts for Glocks along time ago. Nothing but stock parts in my 4 guns, and the only mod is to shave the Trigger Safety down until it is flush with the Trigger Face when depressed instead if sticking up and making a groove in your finger. A G34/35 extended slide catch and mag release complete the guns.
Also the 3.5 lb connector is a mistake as it promotes "Mashing" so leave the 5.5 lb connector in there and learn to use it. All 4 of my Glocks have exactly the same Trigger Pull, so no matter which one I pick up it runs exactly the same as any other Stock Glock...
If you look at Glocks in their proper context as "tools" you leave them alone and just shoot them, then all of a sudden all the problems with Glocks magically go away.
The idea of buying "enhancements" for your gun as a substitute for shooting training and practice, gets you back to being a Golfer or Fisherman and thinking the new Lure or Putter will improve your scores.
Randy