Though in real life I guess the prop might be windmilling
True. But if you had the presence of mind it would be windmilling in coarse pitch (assuming a constant speed prop). I'd LIKE to compare the difference between a prop windmiling in coarse pitch and one under idle power in fine pitch, but that's beyond my nerve/stupidity. I always do power-off exercises in fine pitch hoping that the two will balance out, more or less.
Of course if you have a fixed prop this is all irrelevant.