[spectralblu]

I had encountered this in the lower div general education courses at my university. The most egregious one was the professor who required us to get the current edition of the textbook (since he would be assigning problems out of the new book, which was just a shuffled version of the previous version) that he wrote himself. Fitting that it was an economics course.

Once I got into the CS courses, most if not all of my professors just provided PDFs of either their own material or some open source textbook they were contributing to.