"Surveillance" vs. "open mike"

By now most people who follow current affairs have heard of this incident that occurred after the conclusion of a Congressional hearing, when two of the participants did not realize that their conversation was being picked up and broadcast by an open microphone:

The director of the National Security Agency was overheard offering a round of beer to the FBI's second-in-command following Tuesday's congressional hearing on the NSA's controversial surveillance programs.

The three-hour hearing had just wrapped up around 1 p.m. when NSA Director Keith Alexander turned to FBI Deputy Director Sean Joyce and praised him for his testimony.

'Thank you, Sean,' Alexander said, according to a clip of the exchange that was first reported by Ben Doernberg. 'Tell your boss I owe him another friggin' beer,' he added. 

Video of the exchange at the link.

The best commentary I've encountered is this one from the Reddit thread:

"It must be terrible for him to have a conversation he thought was private heard by other people who might now use it against him."