I was under the impression that polyfidelity meant the same as your typical monogamous relationship: no new partners, ever, and even bringing it up might cause you to be dumped. Difference being, it would be with more than two people involved.
I thought it wasn't for me, in the same way monogamy wasn't for me: even though I didn't have anyone in mind, the concept of "if you fall in love, too bad! It's not allowed!" felt way too restrictive to me. Because polyfidelity seemed to me to be the same, I was similarly not too interested in it.
However, if it's "if you have someone you like, you need to tell everyone about it, and we'll all work in making that relationship work and adding it to our family"... Then, it sounds exactly like the relationship we have, the one I'd feel most comfortable with. No casual sex, no dates prior to warning everyone, we all get to meet the person or hear about him/her and see pictures, things like that.
But the relationship isn't really closed, the network isn't "complete". It is... until one of us meets someone.
So I don't know if that qualifies as polyfidelity or not. It seems to me polifidelity involves having a "complete" family that never gets any more members... Like a traditional couple.