that you know a group of people who are good at predicting and habitually disagree with them.

It seems to me that this is exactly the sort of thing that can really happen in politics. Suppose you have two political parties, the Greens and the Blues, and that for historical reasons it happens that the Greens have adopted some ways of thinking that actually work well, and the Blues make it their practice to disagree with everything distinctive that the Greens say.

(And it could easily happen that there are more Blues than Greens, in which case you'd get lots of systematically bad predictors.)