I agree with LY. This board to me is one of the most respectful on the Internet as a whole, in any subject. Amazing amounts of info can be gleened from many levels of diving.
On the dir hose stuff, my take is that many times in an ow setting all of the specifics are not obvious, but as diving possibly progresses to tech, cave, penetration, deep, scooter, stages, deco, etc. some of the configuration info comes into light. This is part of the little talked about holistic approach to diving that is the mainstay of DIR.
In the new Dir Fund book JJ even wonders if the long hose is even needed at all in easy ow settings.
The thinking on the long hose primary is to know that the reg you are donating is working and can be delivered immediately in addition to the possibility of someone just pulling your primary reg out of your mouth.
Tommy