Hi
@doctormike
No, always on.
I nearly exclusively dive solo, my pony is my emergency gas supply only. The pony 2nd stage and a full size SPG is right in front and below me, I don't think I would miss a free flow, have not had one to date. It's extremely unlikely that I'm randomly going to run into an OOA diver. If I did, I would do what I said above, quickly hand them the 2nd stage from my pony and then figure out what to do. I would have the option of keeping them with me or handing off the pony, if that seemed appropriate.
There have been several threads discussing always open vs. charged and off with strong opinions on both sides. For those deciding on a back mounted pony, which would be always on, the likelihood of spotting a free flow is probably lower.
Good diving,
Dr. Craig