Bill, you must be talking about properly cocked hammer guns. I cannot remember the last sxs shoot I was at where I did not see a target launched, and some shooter with a double trigger hammerless gun swing on it, pull on the trigger and when nothing happens say something about the "damn safety". I am often one of them.
Most reliable shotgun: single barrel hand cannon with large touch hole and kerosene torch. Every device added after that increased the probability of mechanical and/or operator failure.