I find it funny how so many "classy" Nebraska fans try to make everybody else act in a way that they deem "classy". Get off your high horse, its not like they are handing out batteries to throw at the visiting fans.
I don't see this as "classless" I see it as a harmless prank/joke/whatever that will hurt nobody, and let some hurt/angry/upset fans vent their frustration. Sorry for all the slashes/.
Even if you deem yourself "better than that" it doesn't mean that its classless, rude, etc, etc... Let the students do their thing.