$5/pint for a locally made beer seems really reasonable to me, unless the beer sucks.
I'm certainly not complaining about the price of the beer at the brewpub, just anticipating a high stadium markup. Though I was just told the other day that their beers sell for $6 at the park, which is comparable to the "premium" beers at the regular concessions (Amber Bock & Corona). So certainly a good deal.