I want to thank everyone for their thoughts on what is clearly an important issue to me, and I'm glad to see that others feel strongly too. I also want to apologize for posting the quote with a name on it, because my question was raised by the quote but I did not intend to question anyone's actual behavior in that situation, which I obviously don't know anything about. It raised more of a hypothetical question for me.
I'm still at the thinking stage about hard and soft limits, and to the extent that I've interacted with anyone I've had occasion to learn that I have issues and limits that I never would have guessed at, so obviously you can't predict everything in advance, including what you might enjoy that you are too timid to try. I still see part of the issue as being under what circumstances the Dom/me chooses to push.
One of the things that happened to me recently was that in the throes of some kind of submissive haze I allowed some things that hadn't been previously discussed at all, but that I have to say no one in their right mind would have thought of as limits at all. There was no way my partner could have predicted that these would be issues for me, so I place no responsibility on him, but in fact I was extremely freaked out afterwards and still am. And I guess that's why I react to strongly to the idea of really being in subspace or whatever and having someone push something that I actually knew would be a problem for me. I think I would do it, I think the more challenging it was for me that more I would be willing to do it, and I think I would be a basket case afterward. So maybe I'm not cut out to cede this kind of control to someone.