I agree, we can define bbs as a "true" bbs, in the meaning of no(!) stubble can be felt, regardless how hard I try to.
But, as we all know, a good shave will be never objective (with bladefeel... without... very wet lather... thick lather... creamy lather... quick strokes... slow strokes... using an aggressive razor... using a comfortable razor... very sharp blade... more comfortable blade... etc.) and that's fine with me.
And as we are human beings, aiming for perfection, but honestly rarely reaching it, I think, we can say, subjective bbs (or just a good, really close shave) is what you can get within the limits of what you call yourself a comfortable/pleasant/enjoyable shave, plus a satisfying/gratifying result.
Still, it is interesting for me to read, what you call a bbs result, within your subjective point of view.