He makes some interesting points in that video. Pretty good video.
Just a quick story to start. As it happens, we had big honking locks and chains on our 5-stand traps which had been sitting out for years in NM sand storms. Come time to more a trap, I soaked 'em in WD-40 and heat, got 'em open, and still ended up taking the locks into a smith. They ripped me for using WD-40. I was a bit shocked, but a big no-no from them on locks. Kerosene, Marvel Mystery Oil, anything other than WD. Just an FYI on WD-40.
Ok, so the coefficient of friction between steel and steel is .8 dry and .16 lubed. So, for instance, 10 lbs of force dry steel-on-steel is actually 8lbs (10 x .8). Put some lube on that, oil or grease even water, and you now have dropped down to 1.6 lbs (10 x .16).
Now, steel definitely holds lube in the surface pores unless you do something to remove it - i.e., strip clean it. And, obviously, if we strip it, then we're going to reapply lube to restore the coating. I really don't worry about corrosion, just wear. I don't know about you, but my guns are wiped down after use.
My experience says to apply a light film and then wipe it off leaving a film behind. It just helps the coefficient of friction.
The thread about spray it down w/ Rem Oil and shake it off holds some merit. I actually use Rem Oil for a cleaner and then wipe the surfaces down and add just a teeny dab of Mobile 1. Rem Oil is thin, penetrates in aerosol form, carries dirt out with it, and leaves a film (maybe not the best but a film nonetheless) behind.
I have jeweled surfaces on the faces of my O/U barrel blocks. I and most of the people I shoot with (Kreighoff, Perazzi, Guerini) will take a fingertip of light grease and rub it over those surfaces to protect those surfaces during an afternoon's shooting. Will oil work? Yes, I've used it too in a pinch. But, grease gives better protection in rubbing areas most especially if we take care of them and don't let dust and other crud build up. But, grease does attract more dirt, unburn gunpowder, etc, no doubt.
In the long run, I'll do it my way, and you do it your way, and we'll all be happy, happy!