How can fair use benefit you as a teacher?

After the little reading I did, it seems like fair use is fairly ambiguous. There is no set of rules or even any real guidelines for what I can and can't use in the classroom. From most my reading, they suggest that as long as you cite the source if available and don't use too much of it and don't then publish it under your name (or essentially plagiarist) than you are ok. I think that the fair use regulations can benefit us because first, the likelihood of getting caught is slim to none, and second, there seem to be so many reasons you can get out of a lawsuit, it just depends on the situation. I think if you can prove that it is enriching your classroom and not harming the quality or monetary value of the work, than it probably won't be a problem. I think this opens up all sorts of information venues to us to help make the classroom a more exciting place.