When I go to the football games here (and I go to every single irish game)....I seriously grab a crappy Adidas drawstring laundry type bag.
Students (and I'm sure other people at normal games) are drunk, kicking over things, etc. I would NEVER take the chance of something happening. Plus it's not like they wash down the concrete after every game, etc.
In fact.....gross story, but I was at a concert in Detroit last summer and these drunk guys behind me spilled beer on me 3 times...we moved up a row and then they actually urinated on the people who moved into our spot.
That's why I would never take my LV to any type of big public event like that.