Yes, "universal consensus" is way, way too much to expect of the universe. But I'd claim that the current contents of the News.YC front page represents a broad, fuzzy consensus, plus a few outliers, and that's what we're trying to signal here.

I actually expect that, were we to implement this idea, the "X users have pressed the Fake Traffic Light button" widget would always register a certain number of clicks for the average front-page article. You're right -- the median submission will always seem annoyingly offtopic to somebody. That's why I think it's important that the "Cold Shoulder" widget be very small and unobtrusive, since it will always be there, registering something.

And, of course, for the median submission the widget might well have no value, since it will always register some background noise. But my hypothesis is that the design might pay off by keeping the objections small and inconspicuous, rather than having them eat up space on the main page the way curmudgeonly comments currently do. Meanwhile, for the non-median submission, the feature will come into its own: If you submit a link that recruits people to the Hare Krishnas, and it gets zero upvotes plus 75 "Cold Shoulders", you can't pretend that your article has merely slipped through the cracks. Nope, we're actively ignoring you and hoping you will go away.

Of course, perhaps my idea would just end up encouraging rebellious users to compete to rack up the largest possible tally of Cold Shoulder clicks. If that turns into the game of choice I might have to concede that my idea is terrible. ;)