No, I do not think it "easily exploitable". I think if it exists, it probably inside the vig. The sharps would know for sure, but they could well have experience that teams like ND get more action than teams like Arkansas, and the action is, in part, biased by fandom. So, some percentage of bets on ND is influenced because their fans are numerous and think highly of their team. The sharps then set the opening line with this in mind expecting to get some initial emotional money, and then over the week the line creeps down a bit as smart money comes in.