It would likely be trivial to win on the grounds of fair use for educational purposes. Upper education that relies on graded homework is, in my opinion, broken anyway. In engineering, my greatest course experiences were those where the answers were given in full when the exercises were assigned. The feedback you get by checking yourself while you are doing the work is immensely more valuable than getting graded papers returned weeks after you've done them.
This, of course, allows people who don't want to learn to avoid learning, but it's the university's job to certify that you have learned things and make available the resources to learn. Policing you to learn with the graded assignments game leads to a lot of people who are really good at playing, not so good at having interest in their work or the actual material. (I knew so many people who succeeded through grey-ethical finding answers through peers and instructor's guides ... 10 people collaborating to each to 1/10th of the assignment, etc.)
This, of course, allows people who don't want to learn to avoid learning, but it's the university's job to certify that you have learned things and make available the resources to learn. Policing you to learn with the graded assignments game leads to a lot of people who are really good at playing, not so good at having interest in their work or the actual material. (I knew so many people who succeeded through grey-ethical finding answers through peers and instructor's guides ... 10 people collaborating to each to 1/10th of the assignment, etc.)