I think Mizzou may be kind of caught in a dress code dilemma, LOL. I am at that age when everyone has kids in college, and Moms who are Mizzou alums are a bit bewildered that the sororities are nudging members to dress up a bit for games now that the school has joined the SEC. It's not part of their tradition.
When I was in school we all did it; now it is mostly the greek organizations who keep it up at some schools, which I understand is what is driving it at Mizzou. (Not at LSU, though, where everyone who actually attended the school tends to do it. We stretch the color wheel a bit to include lavender and pale yellow, and even dark navy blue and tan, if worn with either purple or gold. That gives you more room to buy a nice outfit that isn't JUST for games. Alumni men in Louisiana are particularly fond of purple and white gingham button-down dress shirts, which they usually wear with khakis.)
The level of dressed-up is about what it might be at an outdoor daytime wedding, except that everyone is wearing variations on the same 2-3 colors, and there is an inexplicable fashion for
cowboy boots worn with dresses, which I *think* was started at 'Bama. This photo is from the Grove at Ole Miss, but the clothes are pretty typical: