This is also, at least in Canada, why most security cameras only record video and not audio. If two people have a conversation that is recorded without their knowledge, you don’t even have one-party consent. You can record video in public but not audio.

Edit: where I am we have one-party consent rules for audio recording. I can have my phone in my pocket recording without you knowing just fine. But I can’t tape a microphone to a park bench and record the conversations there that I’m not a part of.