The study revealed that, while transparency about good news increases trust, transparency about bad news, such as conflicts of interest or failed experiments, decreases it.
Yes, that’s generally how a Bayesian agent would determine the extent to which an institution is trustworthy. A failed attempt to hide “bad news” would be stronger evidence that an institution is not trustworthy than a frank admission is, but that frank admission is still a reason to revise one’s estimate of trustworthiness downwards.