Almost every stadium to which I’ve every been has a sales office open to the public. It’s in here where the managers and full-time sales staff reside during pre-game. These are the people who can get you that extra ticket or find you a seat to a “sold out” event. Don’t waste your breath arguing at the ticket window, those people are usually part-time and can’t do much. Plus, it’s much harder to argue when there’s a big line behind you and a big plastic window in front of you. Sales offices usually have smaller lines and a counter without a window – this makes it much easier to negotiate.
