The original poster indicated he was doing a conversion from a convential rec-diver setup to a 7' hose.
I was pointing out it might not be the best idea to bungee one of those yellow-octo backup regs around your neck on a yellow hose (if you were doing a conversion of a standard rec-diver setup to a 7' primary)
(The orginal poster later clarified he did not have a yellow-octo backup, but rather a standard reg)
But, That's how we got on the color thing. It occurred to me many McDivers (as some like to call them) are going to be looking for the "yellow-in-the-triangle". So if you are going to do something different & you are concerned about encountering one of those folks needing air, why not put your primary on a yellow hose to give that extra little visual clue? (if you are really concerned about it)
Or is DIR only "Right" as long as it doesn't look like something a DorkDiver might have? (a yellow hose)