I'm not bothered a bit by the practical bickering with this watermill fantasy, sure it has real poetic force to anyone who's turned on by the sweet experience of being bound and silenced, or seeing someone going through that (anything involving full upside-down suspension is a turn-on to me...).

I'm not sure how far I would let it go on within a story without remission, but then it wouldn't be to make the story real but to keep things moving.