As someone more interested in solo diving than buddy diving, I don't make a great buddy, which is fine with me. But of course if there are other divers around and one of them runs out of air and I happen to be the closest diver around, I'm fully aware they're going to be yanking the reg right out of my mouth.
Fine.
In contrast to the DIR/long-hose folks, though, I have another solution for a situation like this that works even better for me: while the other diver sucks off my primary, I either grab my Air2 - which is always handy right there, very intuitive, OR I nod my head and pick up my necklaced pony reg (always dive my air pony - strictly as bailout, not for deco).
Either way, we both get breathing. Now I can pop two straps and remove my pony from the bag (one reason to bag your pony instead of mounting it... another option that works here is slinging it, although I find that gets in the way for close reef photography), pull the reg out of the necklace, hand off the whole pony rig to the other diver, and let them ascend on their own.
No futzing with unwrapping a long hose. No buddy breathing. No uncontrolled ascent due to another panicky diver. No risk of DCS on my part due to an OOA problem on theirs. Each goes up on their own.
>*< Fritz
P.S. Note that this presumes the kind of diving I do, which is strictly open-water, non-deco, non-tech; I understand full well that part of the discipline of being a good tech diver is the teamwork, and especially in overhead situations they simply cannot operate under the same assumptions I do. But that's not me.