What illegal audio? There can be no expectation of privacy on the side of the highway. Additionally, how can the police record me with a body cam that they expect to use in court and then then turn around and say they had no idea they were being recorded and thought they had an expectation of privacy?
While we may think alike on some things when it comes to the law you need to know exactly what is what
Audio recording lies in the domain of the States while video recording lies in the Federal Domain. On video, Glik v Cunnife was the 'landmark' case regarding taping public officials (!st Appeals Court 2012) but now another district (8th I think) has recently come to an opposite conclusion so it is likely we will see a Supreme Court case in the future. Other than that one District you should be safe videotaping Police in public locations as long as you're not interfering with their official functions.
There are some restrictions on this especially while on Government controlled property. There are several threads here on the subject
State restrictions on audio recording usually fall under 'wiretapping' statutes. There are generally 2 types of restrictions. One is "one party consent" or "no consent", which means that you do not need anyone else's permission to record them. The second is "two party consent" where persons being recorded must be made aware of that. And there are variations on this. Here in S.C. it's 2 party direct consent. You must inform whoever is being recorded that it is being done at the first reasonably possible moment, and if any person you are recording denies their consent you must end your audio recording immediately. Consent must be directly given here; only stores and other places which the public can freely access are permitted to use signs letting them know they are being recorded (which is called "implied consent"). And States are allowed to transfer the right of regulation to their Counties. Cities, and Towns if they so desire further confusing the matter
In many places (including S.C.)
violation of audio recording laws is a Felony offense And oftentimes when any part of an article of evidence is deemed illegal, that entire article might not be allowed as evidence so 'muting' the audio on a combined A/V recording may not be enough to allow the video to still be used as evidence
See what I mean? There's a lot to know here-
common sense and logic does not apply in the Law or in Courtrooms You need to look into what the audio recording Laws are where you will be recording then follow them I chose my approach of no integrated audio recording because that is legal everywhere, and I'll let my Lawyer deal with what may or may not have been audio-taped on a separate unseen device which I won't admit to having intentionally used
Phil