Or they were at the wrong library. UIUC's library is actually spread across about a dozen buildings all over campus. The Main Library has about 20 departmental libraries within it, the Main Stacks are 13 floors spread over 10 stories (we have floor 3.5, 9.5, and something else). There are several smaller libraries in various dorms and other class buildings. Our Engineering library is physically large but has few books as it's mostly study space. I'm guessing that's what they saw, and didn't venture farther south to the piles and piles of libraries there.