Getting back to the original question:
There was a sub I'd played with a couple of times, and it had gone great. For various reasons I saw an opportunity to do a kidnapping scene she had mentioned as a pet fantasy, which sounded great to me. So I duly kidnapped her at knife point (switching the sharp blade I showed her for a butter knife to press to her throat), dragged her home in cuffs, and spent a blissful day torturing her into submission and enjoying her abject slavery. Everything seemed to indicate that she had enjoyed it just as much.
Except that the next time she phoned me, she told me I had gone way too far and abused her irresponsibly. Um, but, you had a safeword, right? We did talk about it before, right? Well, yes, she allowed, but I forgot I had it!
So... Consensual or not? Damned if I know. I've had other subs who lost it in the middle of a scene, and I've known before they safeworded that it wasn't working for them; but I didn't get any bad vibes from her at the time. Weirdly, she said that she hadn't been sure if she had been abused, so she asked a friend, who said it sounded like it... How do you need to be told if you've been abused?
So that's my non-consensual story. Or not. You guess.