Are you kidding me? Husband and I are die-hard Bills fans, married 20 years. But if some tool did something like, come to my mother's funeral or my sister's wedding with earbuds & an iPhone trying to watch the Bills game, I would ask said tool to be escorted out. You can be a fan but -- especially today with DVRs, online access, etc. -- not participate in today's constant erosion of good manners and good taste.
It doesn't matter if the bride is a castrating B word from hell -- I wouldn't have a wedding on Sunday during football season either -- but if you accepted the invitation, you have to live with your social commitment.
Or just be a dick and watch TV in church. And be known as That Guy. (As BMWR100RT said earlier.)