American copyright law is intentionally opaque. Outside of legal departments, few students or faculty members have a thorough understanding of Fair Use. Some studies even support an assertion that "no one" on campus understands it.
While this fog is helpful for courts that must continually interpret and redefine the spirit of copyright in the face of evolving technology (i.e., everything to come along since the printing press), the same gray areas can lead to confusion, intimidation, and widespread noncompliance on campus.