As A followup to my previous comment, I found a link to a Massad Ayoob article, for those of you who don't believe that these locks can fail.
Massad Ayoob » Blog Archive » INTERNAL GUN LOCKS
I find Ayoob's opinions interesting and informative. But... a Series 80 firing pin on a 1911 can fail as well. Mechanical things fail. I'm more concerned about the adrenalin rush and inability to think clearly that I would experience if the unthinkable happened, then I am about a fail to fire.