There are a few folks that believe it was all a recent fabrication of Ruger to justify their new model type action, but history tells us very differently. Ive seen references into the 1880s discussing the method, Elmer Keith wrote of it in the 20s and 30s, saying it was widely used, and he learned from those that had been around in the late 1800s. A few that felt they knew better, and he mentioned several people he knew of that had shot themselves in the leg while saddling a horse with a fully loaded Colt SAA.
If you push the near side stirrup over the top of the saddle to tie the cinch, and the stirrup falls back and hits the hammer, its enough force to shear the sear notch in the hammer or break the tip off the trigger. Dropping the gun is another issue with a fully loaded Colt Single Action. I do know one guy that was carrying a Ruger old model 22 when doing fence work and carrying it fully loaded. He impacted the hammer when it was in the holster and shot himself in the leg. He was quite a ways out, and ended up losing the leg.
Ive carried Colts with the firing pin down between the rims of both 45 Colt and 44 spl, thinking it should be perfectly safe. It didnt turn out to be. My holster was a half flap the fitted the gun well, so nothing pushed the hammer back enough to let the cylinder turn, yet many times I discovered the gun with the firing pin resting on a live primer. It would have been safer to have it on the safe notch than resting right on the primer. I stopped doing it.
If circumstances indicated a higher level of concern, Id occasionally load 6, but was very aware of it at the time and pulled one when circumstances seemed to allow.
Going into harms way can have many interpretations. Just everyday life may be hair raising at times, but mind numbingly boring as to day to day details. If going after a known dangerous person it may be justified in topping off for the duration of hostilities.
I do hope nobody brings up the old wives tail about storing money in an empty chamber again....