What not to wear... a Brien jersey though for the game in Pittsburgh you would probably have many compliments.
I suggest the beer belly. Holds just under 7 beers (or 80 oz of whatever you care to fill it with). Never tried it at a warm weather game, but under a coat its undetectable even with a pat down. I don't have enough posts to include a link but just google, "the beer belly" and you will find it for sale for about 35 bucks.
Gotta bring a sippin' seat. Been bringing these for years and highly recommend. They also have a hollow binoculars that can hold 13 shots worth. I can't post links but check out papabert.com On a different note, I have a Nikon SLR, I have yet to try to bring it because I take the train and would have nowhere to put it if they turned me away with it. Has anyone brought an SLR camera with a telephoto lens in with them?