This is a follow on to What's the difference between down-vote, vote to close and flag ? and a recent issue about moderator action: Answer that *is* an answer deleted by mod because "it does not provide an answer"?. I think flags should almost always be accompanied by down votes, comments, and when appropriate a vote to close.
The issue moderators face when dealing with flags is that the flags are not publicly visible. This means that if content is flagged multiple times moderators can see that the community wants action to be taken, but when they do that action it looks like a unilateral decision.