Speaking of concessions, and I know this will never ever fly, but I think it's a great idea.
What about a picnic game? Kind of like nascar rules - allow folks to bring in a carry cooler with snacks or sandwiches or whatever.
I know we don't want to miss out on concession revenue, but what if you sold, say, a picnic-ticket for $20 bucks on top of the regular ticket.
I've very likely not to buy $20 bucks worth of concessions (in fact, it ain't happening), but if you told me I could pay $20 bucks and bring in a couple of cokes and a Publix Sub and a bag of chips, I'd do it every game.
I honestly think you'd come out ahead rather than trying to convince people to buy stale nachos and flat pepsi's for an arm and a leg.