It'd be cool to see thumbs down for a bad post. You give kudos for being a good post. There should be a thumbs down or something for being a bad post or inaccurate info. Like those thumbs down on youtube.
Cool indeed. However, it would be abused and go down hill REALLY fast. One of those things that is only good on paper.
In lieu of such I choose to respond with the CORRECT info and usually a quick retort.