Eyewitness is different law from video and audio recording. And if you began video recording in that scenario after you saw the illegal activity commence that would not be fishing so it is certainly admissable.

Audio recording laws interest me. In Queensland you can record without permission as long as you are one of the parties in the call.

In NSW you always need permission from all parties unless it is to protect your “lawful interests” (a phrase which confuses me).