I can only report from direct experience, and experience reported to me, that there certainly seems to be at least one geeky poly loose social web where this is said with a smile and a laugh... but is followed up with "you're welcome to contact them directly".

I have seen mostly-joking forms to do this in text, too. Yes, really. Again, while it's mostly not serious, there is a serious signal of "no skeletons in the closet".

I suspect this is more about a certain kind geeky attitudes and aptitudes than it is about poly. q.v. "geek flirt".

Oh, and I've also seen "references available on request" after an amicably resolved breakup. Again, within the sub-communities that have this geeky approach to sex and to relationships, it's a powerful signal.

(Enjoying the meta of posting this during a trip to the USA where I'm seeing LDRs, amicable exes and friends within these geeky sub-communities. There's a presentation in a tech conference in there somewhere too, but it's mostly about poly and friends-known-through-poly.)