Actually, pies and pints sales last season were always best on Saturdays. With this sort of scenario, the best forward planning is based on what's gone before.
But we're talking about 14,000 pies;
It can't have been THAT unexpected can it? They didn't make 14,000 pies (or whatever number in excess of that they'd made) expecting to only sell 10,000 and throw 4,000 contingency pies in the bin.*
(* this is based on the assumption that there is no way for them to retain pies made for Friday to be kept until the Birmingham game 2 weeks from now).