Best example of obnoxiousness: Passing out "cheat sheets" to improve heckling.
Reaching your hands out to try to annoy someone is pretty much the definition of obnoxious. So is passing out cheat sheets that instruct fans on how to heckle. Or, chanting "How's your grandma?" at an opposing player whose grandma died the week before. Oh, and here's a letter from a student who was pissed that Elton Brand left school early that basically feeds into the stereotype that Duke's enrollment is filled with people who have no real problems to complain about.
It should go without saying that this was in an era before you could just tweet "fuk u" @ someone on Twitter.