BDSC
Contributor
You are indeed lucky to have that experience.
On the other hand (aside from insta buddy problem) what happens when you take a newer diver out for his/her first few dives to introduce them to the pleasure of diving and to share your knowledge? Do you believe beginner divers are reliable enough too? I did a dive with a new diver recently that forgot what the ascend signal was for. I had to repeat it three times to make him realize I meant for "him" to ascend. He just thought I was telling him that I was going to ascend. He was a nice guy and I enjoyed the dive but he was definitely NOT my redundant air source. I wonder how instructors with new students feel about this type of situation?
By that line of reasoning you should also not dive with a secondary regulator. After all, the primary probably won't fail and your buddy has your back up if it does. Your B/U reg is really redundant redundancy (coupled with your buddies redundant redundancy) so why do we all (except those vintage divers) have them?
Having said that, I can't argue against your, or the OP's, choice. To each his/her own I say.
I've probably been lucky that I've never had to have an insta-buddy and I can see how someone may not feel totally comfortable with that situation. I do believe that in most cases a new diver would be reliable to share air with. It's very likely they have practiced the skill a lot more recently than myself.
As far as a backup reg goes, my line of reasoning is this. I believe in taking reasonable precautions when diving. I think it to be reasonable to have a back-up reg in case of the rare circumstance I or my buddy may need it. Especially if a buddy needs it. I just think the whole pony idea is overkill in the type of diving I do which is the typical clear warm water environment. I feel totally confident in my ability to handle whatever situation may arise in that type of diving without a pony. And it appears the vast majority of the divers agree because only once have a ever seen someone dive with a pony and after the second day he ditched it. To this day it sits in his closet.