The problem is, he may have done that a few weeks ago.
After the 9/11 attacks, Cheney's whereabouts were frequently unknown. And that was on purpose. White House Press Secretary Ari Fleischer coined the phrase "undisclosed location" and it stuck. And no one, save a few with the highest of clearances, knew where it was located.
Enter Joe Biden. Known for his entertaining conversational skills, the vice president apparently thought the topic might be interesting. So while chatting at the Gridiron Dinner last March, he brought it up.
He reportedly told his companions that the secret location was a "bunker-like room" at the the Naval Observatory. This is where all the vice presidents have lived (not together) since 1974.