The law, the strictest in the United States, requires anyone who is recorded to have given consent. The court said people could be prosecuted for recording fans screaming during a football game or loud street arguments, the Chicago Tribune reported.
"None of these examples implicate privacy interests, yet the statute makes it a felony to audio record each one. Judged in terms of the legislative purpose of protecting conversational privacy, the statute's scope is simply too broad," the justices said.
A federal court found two years ago a section of the law specifically banning the recording of police officers engaged in public actions was unconstitutional.