Check out post number 7 above, it can't be a flounce if they still post, in my opinion it's not even a flounce if they still access NSC, which renders all mentioned out of the running.
I'd disagree. For me, the final ingredient required for a classic "I'll never post again" flounce, is when the person does in fact then post again. Ideally they'll just slip into the old pitter patter and appear to be completely oblivious to their supposed "never posting again" status.