As an internet "wannabe" rather than a real-life practitioner, maybe I'm not qualified to comment. But that sort of thing has never stopped me before! So here goes.
This is an interesting post, but doesn't the above encapsulate the difference between sub and slave: a sub still has ultimate control over what she/he will or will not do, whereas a slave has surrendered everything.
But then, thinking about it a little more, isn't anything done willingly simply submissive, even surrendering everything. Surely a slave has "lost" everything: she/he doesn't give - it is taken from her/him. And, by that argument, many of the so-called slaves in this room are really subs who have given everything.