Again, know the situation. Know what you're getting into, know what you'll do if "problems" arise.
I have two girls, 3 and 5. At no point during her life would the 5 year old have been a problem at a game. She does really well in "chaotic" situations where there's a lot of stimulation. We did in fact take her to an Illinois game when she was around 1 year old. Zero problems. Diaper changes were the worst of it, but we knew ahead of time that the bathrooms had changing tables. We did take ear muffs to help with the loud crowd noise and practiced using those beforehand. The experience was perfectly fine - a little extra pain taking the diaper bag and carrying the kid, but really no big deal. I doubt the people near us were inconvenienced at all.
Our 3 year old is the opposite. You couldn't pay me enough to take her to a 3 hour football game. She's very needy and gets stressed out when over stimulated. She'd have a really tough time sitting still etc. Even if she had room to roam around on this hillside, I would go into the experience expecting to watch zero minutes of the game. She'd be miserable, I'd be miserable. Not worth it.