I would assume there are counter measures and detection. I strongly remember people discussing up-voting rings/puppet groups that pushed stories on slashdot and reddit, and the counter measures used to prevent that.
I don't recall if dang has ever openly discussed such security measures, through I do recall him saying that people can loose access to flag/voting if they are misused.
that means two or three people spawn-camping the new queue can control what stories will or will not get through