I would say it requires "A and A->G and not B" and "B and B->G and not A"

such wild disagreement amongst "experts" makes me suspicious of their credentials

I think that's part of what I'm trying to quantify here. when there's little direct evidence(or we don't understand it ourselves), and a lot of thinking, experts are pretty much defined by the opinions of other experts. If we want to guess at the reliability of their conclusions, the only track record we have is how often other experts agree with them.