No kidding!

Years back, in college, I hunted around and bought a copy of the textbook required for a course on discreet math. It was small and very expensive. Later I learned that some enterprising students had gotten a copy from the school library and, at $0.10/page, photocopied it (or at least the parts needed) and saved an ass-load of money.

I have no idea if an open-book test would allow for bringing in a stack of photocopied pages, but ...