What happens when you play Radiohead songs for 30 5th graders and ask them to draw pictures of the music? You get 30 interpretive drawings of the most critically dissected band of the last 5-7 years.
"When you listen to Radiohead, you're no longer actually listening to Radiohead -- you're listening to everyone's opinion about Radiohead."
"Thus, in order to solicit an honest, undiluted opinion about Radiohead, you'd have to find the proverbial People Living Under Rocks. As People Living Under Rocks are unavailable, let's use fifth graders."
I think the teacher's idea is clever and could be an interesting tool to develop imagination. I was a pretty literal kid and could have used some imagination development. If I were in that class and was asked to draw an interpretation of Radiohead, I would have drawn my best 3D stick figure with an AM/FM on his shoulders.