If the kiosks can't get numbers right, and for folks to have to leave the first half fifteen minutes before its finished, just to be sure of getting a hot pie, and for the hot chocolate to taste of stale water, (every home game), and when they run out of crisps for heaven's sake, and when the attendants are paid rubbish money by an outside company that pays no attention to customer service...lets get the historical and traditional fayre right before we try alternatives. Pies are great, in moderation, and one or two a week won't pile on the weight. (but thats a different argument)
And I think taking in your own food is like going to the pictures with a picnic. Its not the same as buying popcorn and hotdogs when you're there.
Hotdogs would be a good alternative to a pie, for those watching their weight.