At a recent shoot a fellow was having some trouble with his Glock.
A Glock Armorer examined it when the fellow expressed frustration about the problem he was having with it (not me, but I was close enough to observe the whole thing). On examining it, the problem was readily discovered.
You see, this fellow had bought his Glock used and he noticed that the trigger safety didn't work and it was having some reliability problems related to the trigger.
It turns out the the former owner, without disclosing this to the hapless buyer, was an active member of the Bubba Cletus Home Gunsmithing School - Motto: "If there's nothing wrong with it, there will be once I'm done with it, ay-uh".
Not happy with the existence of the Glock trigger safety, this super genius decided the solution was to file open the hole for the trigger on the frame so that the trigger safety wouldn't engage against the frame and thus was deactivated. This is a bad idea on multiple levels.
Bubba Cletus thus violated the first rule of home gun-tinkering: When you have an expensive part (the frame - about $150) and an inexpensive part (a $14 trigger bar assembly), and if you decide that you must mess with it, you mess with the inexpensive part.
Of course, the frame can't be fixed and the fellow now needs to send the frame in to Glock to buy a replacement frame as that's not a part you can just order over the internet.
Why Bubba Cletus thought disabling the trigger safety made any sense is beyond me. On top of that bad decision, why he had to compound it by not filing it off the trigger, which would be dumb but easily repairable rather than the irreparable frame.
The trigger safety not only protects the user from an inadvertent touching of the trigger movement but also prevents the trigger and trigger bar from moving under momentum and firing the gun if the gun is dropped. Disabling it doesn't improve the trigger pull or feel and reduces safety and functionality so just don't do it.
More annoying is that he then unethically sold his mistake off to an unwitting buyer rather than having to pay to fix his folly.