There's an alternative: Just don't let yourself get dragged into an argument/deep discussion of the matter. A simple, nonchalant reply that they can't get any hooks into is a good out. You may have to repeat "No thanks. I'm fine." several times. People seem to be deaf to such things if they fly in the face of their perceptions. It's a slow process and leaves people baffled but is effective over time.

Good advice. Indeed perception is the hardest thing to overcome.