My thoughts exactly. On this board, the donating of a known to be working regulator is frequently touted to be one of the big benefits of donating your primary. But you get the impression that the odds of your alternate failing are real in a traditional setup, yet negligible in a necklace setup. Put it another way, why is it not acceptable to put the OOA diver at risk of an alternate failure, but ok to put the donor at that risk? All I could think of was because the OOA diver is more stressed.
I'd like to try a long hose/necklace setup, but I'm not about to replace the excellant training i've received with knowledge from the internet. Thus I have been looking to take a GUE fundies or similar type course. But then I realized, if this new alternate air setup is something I would want to take a course to learn, I would want a regular dive buddy similarly trained. As I don't have a regular dive buddy, and given the state of buddy breathing knowledge in the general dive public, I'm not sure i'd attempt to buddy breath with someone I don't know. And if the reliability of my alternate is a real concern, that precludes me donating my primary.