OP:
I'm not a 1911 expert, but couldn't the trigger actually get pulled if the gun were dropped muzzle up? The inertia of the trigger and trigger bar would continue backwards, like on a Glock. But there's no trigger safety thingy to block it from firing on its own.
The grip safety blocks the trigger bar exactly the same way the Glocks drop safety blocks it's trigger from moving. It's only at the back of the gun where it belongs
on a 1911.
If the 1911 was dropped barrel up. The same momentum force that would try to pull the trigger back would also pull the grip safety back firmly (the grip safety is allready held back by the leaf spring anyways). The grip safety would block the trigger from moving.
The 1911 grip safety is the same levered trigger block as the Glock trigger drop safety. Only the 1911's is on the back of the gun, where it belongs and is hardly noticeable, instead of on the trigger.
It would rock if Glock used a 1911 style grip safety instead of that gay trigger drop safety. Then we could have a nice smooth trigger shoe instead of that oddly shaped rubbish Glock uses. My Glock 23 has wicked trigger bite and alot of that problem is that stupid safey lever diggin into my finger. Even the Glockworx trigger deos it.