Maybe I'm missing the point, but Wednesday's problem is not that "Somebody would have noticed!" is a bad heuristic, but rather, that she (and her congregation) doesn't know what counts as evidence, and therefore what it is she (or anyone else) would even be noticing. (RobinZ looks to be making the same general point.)

I think what you've proven is that you need to correctly compute the probability someone would notice (and say something), staying aware of the impediments to noticing (or saying something). (ETA: "You" in the general sense, just to be clear.)

(If necessary, have an intermediary voice your reply.)