I've worked special security at several NFL stadiums and venues for other sports. No matter where you are, there are going to be some fans acting poorly, often violently. It is not reflection of the team or fan base. How a team has its staff respond is crucial and does vary widely. Several Major League Soccer teams often play in stadiums much larger than they need, which gives them some really effective flexibility. Soccer fans often form groups, parking, tailgating and walking through the stadium together. Some teams give these groups escorts through the crowds when they visit other team's stadiums, sitting them apart from the home fans. It works really well.