nippurmagnum
Contributor
That redundant gas IS your buddy. Most places that allow SOLO diving with proper certification also require proper equipment. When you took your solo/self-reliant class was redundant air required? I can answer that for you, yes. But, as I said, you do you. No one in the world is telling you that you can't do some solo bootleg dive off your own boat or a shore or whatever. I am simply saying it is not prudent to advocate that in a mixed use forum.
Most places where I do solo diving (Bonaire, Roatan, Kona, South Florida, Southern California), dive shops don’t require a solo certification to rent gear, even though I usually make it clear enough that that’s what I’m doing.
And even when diving with buddies, I don’t count on buddies to be a handy redundant air supply for me. I always conservatively assume that buddies will not be paying attention to me, will have their backs to me and be kicking away from me, or will be below me, and will not hear my quacker or my banging on my tank. If my air delivery is compromised (say, by a free flowing regulator, which did happen to me once during a group dive), my personal preference is to make a controlled emergency ascent, rather than to try to reach my buddy or another diver.