If the purpose of flagging is to change user behavior (rather than simply removing unwanted material from the site) it would seem important that users are notified when their posts are flagged, but before they are banned.
Perhaps it would be good to show the "flag" count to the owner of a post, if that owner is not already banned? This might be provide warning to a perceptive user that their comments are considered inappropriate, while not making it obvious to intentional spammers that they need to create a new account.
For the same reasons, it might also be helpful to show the split between up- and down-votes, rather than just the total. Since this is visible only to the original poster, it wouldn't have much impact on the overall interface.