When I am shooting a single action revolver, and the hammer is down on an empty chamber, I would never cock it until it was pointed in a safe direction and I was ready to fire it. And I would never cock the hammer to fire the revolver until my finger was inside the trigger guard, but off the trigger. IMHO, transitioning my finger from outside to inside the trigger guard
while the hammer is fully cocked is dumb, dangerous and more likely to cause a negligent discharge than having that finger inside and off the trigger before it's ever cocked.
This is how I have always fired my single action revolvers and I've never had a single complaint from any of the many range officers I've known and worked with. In fact, I can remember seeing anyone at the firing line cock their single action revolver with the finger still outside the trigger guard. If your personal range wouldn't allow this or the range you officer on wouldn't allow such, rather than call you an idiot, I would simply smile and leave.
Frankly, I'm sorry I brought the question up, because I think some who have replied "not on my range!" aren't even reading my question or understanding what I am asking. Maybe it's just me. But I'm not talking about quick draw, twirling a pistol or running around the range pointing a loaded gun in unsafe directions with my finger on the trigger or inside the trigger guard. And I am definitely not trying to invalidate
Jeff Cooper's most excellent RULE #3. Or any of his fine other rules.
Here is a recent video of
Mike Beliveau (Dulist1954) on YouTube firing an original Colt 1851 revolver. As you notice his finger is inside the trigger guard before he even cocks the hammer for the first round, and his finger doesn't come out as he recocks and empties the pistol. This is what I am talking about.
If you still insist that how Mike and I handle a single action revolver is somehow danger, I will bow to your greater wisdom and will consider this discussion a horse sufficiently whipped and dead.