At 20-1 you don't have to risk a lot to get a really good return. They are playing better the last couple of weeks. I mean they had Carolina (home)on the ropes and that was with 3 Luck interceptions. A big W over Denver didn't hurt anything. Look how quickly things change in the NFL. Atlanta and the Pack aren't playing so good right now, Pats, Carolina, Cincy, are the one's that are elite right now. We have a bunch of middle tier teams and quite frankly it's hard to pick the winner of the games when there are so many teams that aren't consistent from week to week.
Back to the original post, a small bet would give you a nice return if they did pull off a miracle. It's not any different than losing a 50-50 game ats except your bet should be a lot smaller.
Carolina at the 12-1 sounds like a really good bet to me.