One that I didn't want to include in the post because I felt it would make it too inflammatory is this reaction to a particular conspiracy theory.

If anyone's read the book "Matilda" (yes, yes, fictional evidence - I remark on plausibility only), they may remember the chillingly feasible technique of the abusive headmistress to pull stunts so outrageous that the students can't get their parents to believe them. Surely someone would have noticed if the principal of a school had picked up a girl by her pigtails and flung her.

The heuristic of dismissing things that it seems someone would have noticed probably usually works, but the things that it wouldn't work on are really big, and so I'm wary of it.