Third, it matters (a lot) whether there is a "reasonable expectation of privacy." DO NOT CONFUSE WITH PHOTOGRAPHY, WHICH HAS DIFFERENT RULES THAN AUDIO. So the fact that video recording is happening has little to do with whether audio is allowed. Now, if you are in a public place (airport) and if you have having a loud interaction (calling to your significant other 20 feet away), even if you are saying something intimate, you don't have a reasonable expectation of privacy. But if you are talking quietly to a ticket agent, at the counter, you might have a reasonable expectation of privacy for the conversation. On the other hand, if you are at a TSA checkpoint, and especially if there is a sign saying "Audio and video recording may be in progress" then neither you, nor the TSA employee, nor the LEO, nor the stranger standing near you probably has a reasonable expectation of privacy..
What if I am at a checkpoint and there is no sign indicating that audio recording is in progress, do people still have reasonable expectation of privacy the same way they would have when talking to ticket agents? I would think there should be a reasonable expectation of privacy here considering that people would be without shoes, some of their clothing off, and be subjected to questions and pat-down treatment that ticket agents don't do. As stated before, I surely wouldn't want the whole ideal recorded but it is being recorded on video; however, I would think wire taping is something they can't just bypass as easily. This is why I never see any video from airports, convenient stores, as well as bank with audio but all police dash-cam videos show voice.
Basically, I like to be able to have a leg to stand on and call out violation of wire taping if someone ever wants to use anything against me.