about the same old debate.
I skipped the middle parts of the thread since the beginning and end said familiar things.
Although it's a generalization, and has some exceptions, the long hose primary is found mostly in technical diving. in fact, the long hose is a cave diving innovation to allow 2 divers to pass through restrictions in a line. initial usage called for the hose to be stowed and for the diver to breathe off the short hose, donatng the stowed long hose in an emergency. breathing the long hose as a primary is a later refinement of the technique.
I dive the long hose in technical dives, and haven't had an issue with out of air drills as the donor even deeper than 200fsw.
For sport diving applications, a properly (emphasis here on properly) maintained and secured alternate has not posed a problem on any of my dives. not even the two real alternate air ascents i've had to make (once as a donor and once as a receiver). In fact, I find that for teaching sport diving, an octopus is an invaluable safety tool, and I wear mine on the left side for ease of access and control when evaluating student skills.
A part of pre dive procedure is to review air source location and use with my buddies. in reality, unless i don't know my buddy, or i haven't trained them, i don't review that specific as part of the plan, but if i don't know you, you betcha i'll review that. and on technical dives, I always review this aspect.
my discussion doesn't even address other configurations like an alternate inflator, pony or spare-air type accessory, which can complicate the discussion even further.
i see viable uses for most of these alternates, and the only one i have a problem with is a diver who has none at all.
geoff