This whole discussion is most interesting. Caused me to further "research" on the web. Only found one instance of an accidental discharge thumbing the cap on the "tube" - Cuts Crooked had his thumb "peeled like a banana" and blackened, and he lost all feeling in it permanently. Happened 30 or 40 years ago, and there was some discussion as to maybe caps being made differently today, lead styphnate. I don't know.
Of millions of caps being made, one could be defective. If it detonates, your thumb is getting blasted with the blowback from your chamberload of blackpowder.
Another safety consideration is keeping your off-hand digits away from the front of the cylinder.
And, as noted above, Elmer Keith wrote of raising blood blisters on his thumb from caps exploding while he was seating them (again, an older, different type of cap?)
A dowel seater might be propelled back at you.
And seating with the hammer, a detonation would send the full powered ball down the barrel - (pointed in a safe direction!) A detonation from a detached cylinder would have less force.
Not taking sides, or arguing with anyone's point of view, just fueling the fire. We're dealing with things that have an element of danger to them, which is part of the appeal of the sport. I doubt any will change what they already do, and I don't know that they should. Just something to think on...or not. Shoot on!
