Well, this is why I said that I might be missing something. So, please explain to me how one reaches back and removes a tank with a deployed regulator from the bungees, and how long this takes. What do you do if your buddy does not use sidemounts, and you have to trade bottles back and forth?

I have put a d-ring on my waist just in case others in my team do not have the same setup. So, I can clip a bottle on the side in a pinch.