Loose Lips Sink Ships?

Bruce Schneier recently wrote about the keeping of secrets in the world of international espionage. He discussed the American supposed cracking of Iranian encryption, and made the point that keeping secret that you know other people secrets can be very valuable.

During World War II, the Japanese made huge balloon bombs that they release into the air to be carried to North America. The intent was to start fires and kill people. It was of some success. However, 'In May 1947, the New York Times wrote "Japan was kept in the dark about the fate of the fantastic balloon bombs because North Americans proved during the war that they could keep their mouths shut. To their silence is credited the failure of the enemy's campaign."'

Somebody once said about music that the anybody can play the notes, but the rests make the music. Perhaps something similar can be said about security and silence.