Very accurate, I think. I would say that TFTB simply means that the sub is in control of what is going on, guiding events (either by planning beforehand or during the events).
The fact is, a lot of people who like some aspects of BDSM (and I don't think you have to like all of it to fall under the umbrella) will end up with a partner who is happy to participate while not being a big fan themselves. There's no shame in that - just the way life works out. So if I was a submissive and ended up with a partner who was happy to play dom but did not know what to do, I'd definitely be TFTB to begin with, and maybe even forever after. It would still be BDSM I think, just that the D/S aspect would be a little odd. Nothing wrong with being a little odd though :-)
But maybe I have a different idea to what BDSM encompasses than others:
When I'm submissive, I enjoy being tied up, told what to do, maybe spanked in the process, having sex and getting pleasure out of all of it. I do it because I enjoy it, and ideally (but realistically, not necessarily) because my partner enjoys it. Do I therefore not fall into the BDSM category? Because: bondage, submission and masochism would seem to me to be BDSM.