Here's my little related story. I was in one of my fave used book stores (Baldwin's Book Barn in West Chester, PA) which is not exactly close to where I was living at the time. After browsing for an hour or so and picking out a few books, I spied a title on a top shelf that I thought was interesting but couldn't remember ever seeing before. I pulled the book down and began perusing it, and on the inside cover there was a familiar-looking stamped bookplate that said "Property of <My Name>." I was a little freaked out because I couldn't remember ever owning the book. After thinking about it a few minutes, I dimly recalled lending the book to somebody years ago and I guess it was never returned to me. When I went downstairs to the checkout counter, I showed the older man working that day my ID and the bookplate while telling my story, saying I never got a chance to read this book. He very kindly told me to just take the book and didn't charge me for it, saying "I'm just glad it found its way back to you."

What a lovely story, thank you for sharing.

It depends what the class was for. I had a sort of similar experience with a physics class where the professor would take a break mid-exam and just give everyone the answers, but it was a class that was a prerequisite for engineering students who didn't care and really didn't need to, and also a stepping stone for the passionate physics students who did care, but would do the heavy lifting later. The prof was well-regarded for spending his time more on helping with true understanding for the students who cared.

That describes my entire education.