I think its really, likely insanely unlikely, that these guys were at Calhouns. Its about as unlikely as the big wig meeting that happened at Olive Garden.
First off, why risk a public spectacle youre eventually going to have to explain and/or to try to control information from every person who couldve been in or around Calhouns at that time. That is a lot of people, employees, and bystanders.
Second, if youre a VIP at UT with access to a skybox and want Calhouns, youd get Calhouns in your skybox. Theres no reason to go there for the food. See also the point above.
Its not impossible by the literal meaning of the word, but it is unlikely by the literal meaning.