Kirik Jenness at MixedMartialArts.com asks Did Anderson Silva Fight Dirty? and provides a good deal of evidence that Silva did. There was the questionable knee (to the face?) while Sonnen was down, Silva grabbing Sonnen’s trunks, and the most blatant violation, at least in my opinion, Silva spreading grease from his face over his arms and chest.
Are any of these violations enough to change the ruling of the fight. Of course not. Are any of them alone so bad? Not really. Except for the spreading of the grease, they occurred during the heat battle. Taken together though, they seem to show a fighter truly concerned about the other guy’s chances of winning. That should be some consolation to Sonnen.