It's probably the latter. I don't think there's a great deal of awareness on the part of students or faculty of what the copyright law says. It is the role of the librarians to educate and inform users about copyright as and when we have that opportunity. When librarians wish to offer electronic resources for their patrons, the publisher is likely to ask them to sign a contract. Libraries have entered into a series of agreements with many different publishers and producers.
Money changes hands.
We agree to use the resources in a certain way. The licenses libraries negotiate with publishers are pretty broad based. They actually give students and faculty a lot of leeway and a lot of copying rights. Most of Yale's licenses let our students copy, print, and download. The barrier happens at the point of large-scale redistribution or commercial use, but we do try to write contract language for each of these resources that gives our users latitude to do whatever they need to do in the course of their educational research and scholarly work.