This article describes the fans arrested at games in Green Bay. Not surprisingly, Bears games and Vikings games have the most arrests, and most of those that they arrest are out-of-town fans, although the stadium staff claims (unconvincingly) that they don't target opposing fans.
I laughed when they mentioned how many more arrests there are for night games than day games, and they blatantly cite that you have more hours of drinking prior to the game if it is at night as opposed to being at noon. No sh*t, sherlock. The most drunken event Dan and I have ever attended in person was the Wisconsin / Nebraska night game (Nebraska's first game at Madison) which started in the evening and the parking lots were completely packed by 6am. That's 12+ hours of solid drinking before the game even starts, which brings out the best in everyone.
Another factor is that if the Slack fans are found being drunk, they can take away their season tickets, which is a giant disincentive. They'd probably kill themselves or their family would kill them on their behalf if an arrest or ejection caused the loss of those tickets. Once a friend of mine got a ticket for smoking on Dan's Bears' tickets and we received a warning which sucked but hey we are in section 17 out of 17 sections so it isn't quite the same as losing tickets which represent literally the only interesting thing to do on a Sunday in northern Wisconsin.