IF the cops are at the game as spectators, theres no reason they should have special privileges beyond the average spectator.
IF they are there as undercover, thats a different story all together.
From my limited prospective, giving LEO 24/7 responsibility is one of the problems a cop encounters. He's never giver the opportunity to just be a citizen and decompress from the responsibility of being a LEO. Of course there are those in LE that think that because they are in LE, they are special and deserve special treatment.
Football game, off duty cops and no gun gives them a taste of how we feel when we are prevented from carrying our EDC because of some liberal dumazz rules.