REASONABLE GOOD FAITH FAIR USE DEFENSE
Section 504(c)(2) of the Copyright Act says that employees of nonprofit educational institutions who are found by the court to violate copyright cannot be help liable for statutory damages if the court believes the employee had made a reasonable good faith decision that their use of the material was coverd under Fair Use.
Congress included this provision because they knew that Fair Use is murky and grey. They included this provision to encourage faculty to use materials under Fair Use with a little more confidence and assurance.