I thought the same but I guess if your library has 500,000 items, multiple storage locations and 1000s of people that can borrow things, not always with permiss

I thought the same but I guess if your library has 500,000 items, multiple storage locations and 1000s of people that can borrow things, not always with permission and not always recorded correctly, I can see how you wouldn't want to cry wolf until you had searched everywhere. Probably 20 years ago, they wouldn't have had all the security and CCTV that we have nowadays because it's so cheap.