“Audio and audiovisual recording are communication technologies, and as such, they enable speech. Criminalizing all nonconsensual audio recording necessarily limits the information that might later be published or broadcast -- whether to the general public or to a single family member or friend -- and thus burdens First Amendment rights. If, as the State’s Attorney would have it, the eavesdropping statute does not implicate the First Amendment at all, the State could effectively control or suppress speech by the simple expedient of restricting an early step in the speech process rather than the end result. We have no trouble rejecting that premise. Audio recording is entitled to First Amendment protection.”

~ Judge Diane Schwerm Sykes
(1957-) Federal judge on the U.S. Court of Appeals for the Seventh Circuit, former Justice of the Wisconsin Supreme Court
in the ruling for the U.S Court of Appeals for the 7th Circuit, ALCU of Illinois v. Anita Alvarez (2012)
http://www.aclu-il.org/wp-content/uploads/2012/05/Alvarez_ruling.pdf
http://www.aclu-il.org/aclu-v-alvarez22/