The audio/video recordings are only protect if the conversation taking placed is viewed as private. It is perfectly fine to record audio/video of something in a public place, especially if it is obvious you are recording it. This is why CCTV and TV camera crews don't have to get your permission to video tape you.

See this TSA webpage:

TSA does not prohibit the public, passengers or press from photographing, videotaping or filming at security checkpoints, as long as the screening process is not interfered with or slowed down. We do ask you to not film or take pictures of the monitors.

http://www.tsa.gov/travelers/airtravel/taking_pictures.shtm

After that paragraph it does state that certain local laws may prohibit you from taping it, my above point about privacy comes into play here.