Always carry a manilla folder with you everywhere you go. In this folder, have a print-out of a spreadsheet. Any spreadsheet will do, but it helps if it has a call number or two on it. When the library director busts you as you're wandering the stacks with your cup of coffee, produce the manilla folder, pull a random book from the shelf, check your spreadsheet, and replace the book. "Everything's fine here!"
Manilla folders are also valuable when you get busted sitting in someone else's office gossiping, trading advice about job offers, or just catching up on one another's weekends. As the boss passes by, say, "I'd tweak the numbers a bit and see if you can't make those figures match up," then pass the folder to your accomplice.
Never underestimate the power of a manilla folder.