It's really simple - if you don't want a ton of Cub fans buying tickets to watch the Cubs play in Milwaukee, the Milwaukee fans need to stop selling their tickets to them. Easier said than done if you ask me, especially when selling tickets to one of these games probably fills a car up with gas at least 3-4 times. Look at the series against Houston - when Brewer fans can sell the park out to watch them play against a last place team, they could easily do the same against the Cubs if they couldn't bear to watch the game from home and get some extra spending cash in return for their tickets. I think building a larger season ticket base would also go a long way - which is a very difficult task for baseball's smallest market, even if the team's playing awesome. I'm sure a bunch of these tickets were bought before the season started by Cub fans, but I guarantee that at least half of the Cub fans at Miller Park this series bought their tickets from someone selling them online, or from ticket scalpers/brokers outside the stadium. If I'm a season ticket holder and some schmo offers me 10 times the face value of my tickets for the game, I'm probably selling them when it's a series in July, and I really don't care if he's wearing a C or an M on their hat - their money's good either way. You see tons of Cub fans in St Louis and tons of Cards fans in Chicago during their series, too - I think they're just more used to looking at each other than Brewer/Cubs fans. I've had good times going to the games both at Miller Park and at Wrigley Field, because I've spent a majority of the games watching what's going on in the field instead of looking at a bunch of idiots screaming at each other. People looking for confrontations will always find others to start them with, but IMO those people aren't worth even acknowledging. You're never going to have Miller Park 95% full of Brewer fans during a game with the Cubs when there's millions of Cub fans living within 100 miles of Miller Park down in Chicago. Chicago's basically 1/2 as far away from Milwaukee as Green Bay is. Part of it really is a Cub fan's sense of entitlement and a Brewer fan's inferiority complex with being the little guy, but the biggest reason is simply that baseball's smallest market is so close to baseball's 3rd largest market, and there's 81 home games for fans to attend, not 8 like in football.