This is common practice, and a good one. I received my fair share of free food from Calhoun before games against Stanford, Michigan State, Arizona. Donuts, coffee, hot chocolate, pizza, soda...The Arizona game was so cold that they let us in early to watch shoot around because it was unsafe to be outside.
Got some Omar's coffee and hot chocolate from Calhoun outside Gampel before the Texas game in 1993-94. It was December, the night before my Geography final, and I brought my Geography book for 8 hours but merely sat on it. Didn't help the next day, but that was a nice win.

