In the latest issue of Seaworthy,there is a statement in the Mailboat Letters section, to wit: the Distress SOS Night Signal is the only USCG approved nighttime signaling device we are aware of that can be used IN LIEU of flares. My OPFAC is equipped with that light. Does this mean I do not have to carry flares anymore?

I'd have both.

I do carry both. I am in a VE flotilla and would like to yank some chains.

I carry flares in my patrol vest, a spotlight won't fit.

Found it under CFR Title 46, subpart 161.013.
Once more, Google to the rescue.