Is it worse to let go unchallenged a fool making known factually incorrect statements in a professional forum (like a mailing list), or to challenge the fool and potentially have the thread devolve into flames?
From a risk perspective, I view the trade-off analysis as being setup thusly:
1) Let the fool go unchallenged. The cost (impact) is that less experienced and/or impressionable participants in the forum may take the fool's comments as accurate, giving them a life of their own. Overall, this has the effect of reducing the quality of professionals in the industry, leaving some worse off than when they entered the forum.
2) Challenge the fool. The cost (impact) is that the thread may devolve into flames, causing people to disengage, possibly permanently. Overall, this has the effect of decreasing learning opportunities for these professionals, but hopefully does not leave them worse off than if they had not joined at all (though outcome #1 above is still a possibility).
Which risk is greater? It's unclear to me, and strikes me as a lose-lose situation. Perhaps there's a third option that someone could point out.