(2) My impression was that it was public drunkenness which may have endangered themselves or those around them.
I'm surprised you didn't mention the couple seated at the rail who behaved in such as way that they had to be escorted out by the police and security personnel.
It's unfortunate that events like these happened. I've been to many Duke - Carolina games over the years. I'm having trouble remembering a game at Cameron with as much animosity and unsportsmanlike behavior among the fans as this one...... a contrast to how the teams were able to play without such incident.