Academic freedom should have guidelines and restrictions in K-12 as well as on the university level. Of course, professors are entitled to academic freedom, but I believe that it's still possible for them to abuse their freedom (even if the students are adults) and no one should be above some type of guidelines regardless of their degree or status.
Once mandatory schooling is over, students (and their parents who are presumably helping to pay for it) can choose the environment in which they will pursue their academic studies. There are plenty of college and university campuses which promote all kinds of philosophical, social, and religious positions; and they should have the right to do so. What I find so frustrating are the state-financed school which are perfectly content to espouse liberal and provocative positions on all kinds of things but limit or even refuse to allow the other end of the spectrum to be seen or heard. That is NOT academic freedom. Private institutions can make those choices and it is fine; however, when everyone's tax dollars are supporting the school, a more balanced presentation of views should be required.
Yes, I am in full agreement with pohnpei397. There needs to be limitations within the K-12 system. The degree of limitations, however, is contingent upon the culture of a school, for not all schools are the same.
Also, as a teacher I believe the role of an educator is that of a reflective facilitator. Full academic freedom may allow for some teachers to push their beliefs and agendas on students, which--in my opinion--is not what education is about. As educators, we have an obligation to create learning environments that are safe and nurturing for all students. Because of this, we must be selective in what is said/done within the walls of a classroom.
With that being said, I do believe there is such a thing as too much restriction. As an arts teacher, there are a myriad of thought-provoking plays that I would love to perform with my drama students, and I am wary of censorship. Good, quality literature (or drama, or music, etc.) should not be disregarded simply because it challenges traditional viewpoints. If the latter were true, great literary works such as The Catcher in the Rye and The Lord of the Flies would never have found their way into the literary cannon.
I believe that within the K-12 education system, we must continually search for a balance--a point of stasis where students can learn safely and comfortably while still being challenged.
If we are talking about K-12 education, then yes, at least to some degree.
A major reason that it should be is because there are some things that are not age-appropriate. For example, a literature teacher who assigned and discussed a book with explicit sexual scenes with 5th graders should not be able to do so by claiming academic freedom.
As another reason, there are some things that can be said that are disruptive to the educational process. For example, there was recently a discussion here on eNotes about a teacher who assigned her students to describe their idea of a perfect world. One team said that all blacks should be slaves. This sort of thing offends others and makes it harder to learn. It should not be permitted under academic freedom.
For these reasons, academic freedom should not be complete in the K-12 system.