See also Sarah D Bunting's piece on the matter (via MZS):
I would love to tell you that, coming upon a grownup raping a child, in the act, I would grab the nearest heavy object and brandish it and yell at the grownup to get away, and stuff the child into some clothing and drive him to the nearest police precinct. I would love to tell you that; we would all love to tell ourselves that. Everyone's cape flutters attractively in the breeze of the subjunctive.
What probably would happen instead is that I would back out of the room in horror. Flee, in fact, on tiptoe, to somewhere small and dark, to process the upside-down wrong thing I'd seen.