Well, Sid, I've wondered about the earbuds too, but I've never used a set with a mic in them and still had the problem. This most recent time (and, if I recall, at least once previously) it was when I rotated the earbud jack in the nano that The Voice started her maniacal onslought of obtrusive inturruption. So far, I've used the nano a couple of times since I fiddled with the two 'voice off' features and ~ knock wood ~ haven't had any trouble since. What I remember from the last time I had probs with this, though, is that even with the settings 'off' it would sometimes resurrect itself, zombie-style, and begin the litany all over again.
BTW, I added an edit to that post with the instructions. The edit was important because it basically said you can't follow the instructions, not at least on OSX 10.8.2. There's no iTunes folder in Application Support.
Anyway, I wish you luck with yours, too!
V