@ModeWeasel I assume you mean that the preps share with the secondary indie in question - I think that is the case (though not sure how they are used as schools are not forthcoming on that front). But, beyond that, given that, in some of the schools mentioned, a very significant part of the intake comes from state primaries and the the secondary schools don't share the results publicly, I am still uncertain where the numbers come from or how they can be anything else than anecdotal / resulting from a small (and potentially biased / self-selective) sample.
Agree that the reasoning tests are a good proxy for CAT scores - when they are done (not the case for all schools or for all type of reasoning) and the scale may be different - as exemplified by the fact that the numbers being quoted for CAT for Emanuel differ from what is supposedly the cut-off mark for VR for Emanuel.
As a general point, I think that there are indeed benefits in sharing all the information people may have on CAT scores of candidates, successful or otherwise, as long as clear when statements are based on anecdote / partial sample or can be made more categorically (imho).