You chose to name only one example. 'Experts say so' is a fantastic heuristic, which definitely increases the probability of being true. I sincerely doubt you can name enough examples to drive the likelihood ratio down to 1, much less to <1.
'Experts say so' is a fantastic heuristic, which definitely increases the probability of being true.
That depends on the field in question. There are a lot of fields full of "experts" whose predictions are notoriously unreliable.
Related: Heuristics for Evaluating the Soundness of the Academic Mainstream, Admitting to Bias, The Ideological Turing Test