The University/Athletic Dept. keeps a lot of seats held back. I sit in 107 at Gampel. Across the aisle in 108, there are more than 100 seats that are kept back. Coach Blaylock is usually there. The University President is sometimes there. Mora was at a few games when he first came to UConn. For Pine Pluff, it looked like they were hosting a bunch of football recruits.
When I sat in the 200 level, there was a row behind me that was empty for most games. When they were filled, it was usually by student athletes.
There are also the seats that the AD reserves for the opposing team. Some are behind the bench and others up in the corner.
All of these could be released at the last minute by the AD.