I'm sure all of us have encountered the odd sheet not lodged perfectly inside the holder, a motion-blurred image etc. We think nothing of it, of course - live and learn, after all. It's a little different if we make a rare mistake that results in a remarkable gain in ability to visually count out fractions. Sure, I get the common sense argument that your post relies on - at the same time, common sense tells me that there's a risk to using a guillotine cutter in the dark in close proximity of one's fingers, and that this risk results in a rather different (likelihood * impact) product than a mistake fudging some film into a camera.
I'm glad you haven't lost any fingers using your guillotine cutter. On my end, I'm glad to be the proud owner of roller cutter, even though I readily admit that a guillotine cutter overall does a tidier job (on paper, film and bone alike).