Open Courseware is mostly just a dream today. Meanwhile, a $10 billion dollar a year textbook publishing industry is a reality. It is the 800 pound gorilla when it comes to content.
If you Google "Moodle import ExamView" or "Moodle import TestGen" you'll get hundreds of hits where people discuss how to do it. The Moodle Question engine even has an ExamView importer. All of this content is being imported from textbooks. Maybe some of them are open content, but many are surely not. If the students have purchased the textbook for the course, the import is probably defensible. But in many cases I suspect the content has been imported from textbooks that are not required. Every use of such content is cheating publishers and authors out of royalties for the use of copyrighted material.
I have an instructor account with Pearson. It cost me nothing and it gives me access to the online supplementary resources associated with all of Pearson's math and statistics textbooks. I can
download testbanks into TestGen, and I can export from TestGen in Blackboard format, which I can then import into Moodle. Pearson gives me access to their material based on the assumption that my students have purchased the textbooks. However if I'm serving up Pearson's content from Moodle without requiring my students to buy the textbook, I'm doing something wrong.
Incidentally, I went through all the steps to learn how it is done, and I have helped other users do it, but I do not store any of Pearson's content in my own Moodle sites. My students have purchased the textbooks, and they access the content through MyMathLab, which is Pearson's proprietary LMS.
When someone in the moodle community raises an issue of ethics, it usually has to do with things like teachers publishing (in Moodle) content produced by their students under a presumed expectation of privacy (e.g.,
this discussion). So do we protect and pity the poor students, then turn around and
Stick it to the Man when it comes to the big greedy textbook publishers?