At the very real risk of starting another commenting firestorm, here's a little more on that MBA story...
Last year, during a basketball game against University School, MBA chanters unleashed this beaut: "Jew-S-N! Jew-S-N!" An obvious reference to USN's large number of non-gentiles.
USN boy's athletic director Josh Scouten was happy to point out that, during this year's rematch, both cheering sections behaved appropriately. Which is to say, they yelled and screamed and booed but didn't go over the invisible line of common decency that we all know exists and can best be observed with chants like "Jew-S-N!"

