As I wrote above, it is not so much a code problem, as it is a game theory type of problem; you could always cheat by sybill attack, unless there is some form of account verification process and that has to involve manual review...
... I have no idea, what the flagging consensus is, but I think Hive has a pretty brilliant consensus vote protocol thing built-in - It just needs to be used more and tweaked a little, perhaps.
If people were social here they would be able to recognize sybil attacks and downvote them.
That is what that community effort is about, and why it needs input from more users.