Limps:
First, thanks for the correction. I obvously meant a trigger lock. It was late. Thanks.
Second, if your 1911 is like all the rest of the model, as well as pretty much every other automatic, if you chamber a round into the barrel - which makes it "loaded" - then the trigger is active and the only thing keeping it from firing is trigger pressure. In a pack with "poky" things moving around as one walks, that's an invitation for disaster. Especially if, at the moment of the misfire, barrel is pointing at your own back or neck.
Third, of the few actual attacks that occur along the AT or the PCT, only a miniscule number involve the attacker being armed with a firearm. And in most situations, people will recognize that there is something "that doesn't feel right" well in advance. Advice has been given here - correctly - for years that "If you don't feel good about who is at a shelter, or a site, or that you're talking too, trust your gut and move on." That's good advice, better than carrying a gun. So is walking and running away.
I like guns, and have used them, I suspect, even longer than you, for enjoyment as well as protection. But packing one for a thru hike is, simply put, impractical, for the reasons I indicated above, as well as those which others have listed here in an environment that is far safer than most suburban neighborhoods where one walks in the afternoon.
TW