It should be the policy of every college that any student can tape his classes. The student should not be allowed to then sell those tapes. But since the student is paying the tuition, he should be allowed to tape them, even if the prof doesn't like it. In fact, with the coming of podcasts, I think that each college should have a policy where every class is taped by the college, and is kept on file for at least one month. That should persuade some profs from spending 30 minutes of every 90-minute Intro to English class on bashing Bush ans saying that Christianity is stupid. That is what Philip Hu, a teacher of English at Cerritos College in CA does. It is unethical, and if he was properly exposed, perhaps it would be stopped or at least diminished.
If he is in a big lecture hall sneek in and tape the pig
I have NEVER heard it stated that you can't record a lecture without the speaker's expressed written consent. We often recorded lectures, it's a very good thing to do if you want to get all the material down. You can't take it all down verbatim, for pete's sake.
They just don't like the way it's being used. Tant pis pour leur, je dit.