Well it seems to me that, as long as the training agencies don't mandate independent redundancy (pony bottle/doubles etc.) then what logical choice is there? Tell the diver to just inhale water on the bottom and give up?
CESA is an undesirable emergency procedure that can be quite dangerous, so I don't think it should be presented as a get out of jail card to OW students.
Perhaps you think it is so dangerous and so unlikely to be needed that it makes more sense to not teach is explicitly and not practice it and not subject the students and instructors to the inherent dangers. That is not something I necessarily agree with, but it is probably defensible and logical position to take.
But to say we are going to "do away with" CESA could be interpreted to mean that the procedure is never going to be discussed. That outcome would seem to be shortsighted. Particularly since it HAS saved hundreds if not thousands of divers.
I believe in teaching my open water divers to think. My program is described here:
Open_Water+Nitrox+Drysuit-Thavmas Scuba.pdf
It is worth mentioning CESA, as well as its risks. But as a friend of mine who was getting buzzed by a tiger shark while doing deco, he opted for the chamber instead of possibly becoming a meal. Same with OOG. CESA is absolutely the last option, one that does have risks. But getting bent is better than drowining (though the Rouse's are an exception, I'd rather drown than die the way they did).
I'd rather, and I do, discuss redudendancy as well. You can talk about good buddy skills all you want, but buddy separation happens, even to experienced DIR instructors (local incident in my area). What then? For inexperienced divers, having an OOG emergency is likelier during buddy separatation due to increased gas consumption. I teach concepts of self sufficiency. Obviously my students dive in single tanks and are under my watchful eye (as I have only two at a time). But I offer them additional concepts going forward.
I'm just not going to damage my own health doing CESAs with them. I'll do them once at an angle in confined water. I don't repeat if they take a breath. The idea that a student failed because they took a breath is stupid because in the real world people are going to try to breath in. One instructor I was assisting when I was a DM repeated a CESA with one student 7 times because he kept taking a breath. In addtion, as an OOG diver ascends, once the water pressure drops to less than their regs IP, they should be getting some gas.
If I REALLY wants to practice CESA, the way I'd do it is is to have a pony bottle, and dive with my back gas not being full. Breath it down (or dump through my alternate) until no gas is available. Have the pony reg in one hand, and go to the surface at a controled rate. If I can't make it, I switch to the pony reg in my hand. Of course, I bear no responsibility for anyone trying this. We are adults, we have to make our own judgements on risk. That's the way I would do it if I REALLY wanted to test myself to see from what depth I can realistically CESA. But I dive in sidemount or twinsets 99% of the time. The other 1% I'm teaching open water or doing shallow dives.
So I don't.
