That person could leave it blank. But as for the staleness issue you raise - that could be quite easy, the automated contact could be "tdicola, you have receiv

That person could leave it blank. But as for the staleness issue you raise - that could be quite easy, the automated contact could be "tdicola, you have received a message about your jump-ship number", it can list whatever the person wanted to send you, and if it's stale data you could update it on the spot or remove yourself from that kind of search. I would think most people "have their jump-ship-tomorrow price", and updating it whenever you receive an offer that's outdated (and based on old info) means it would stay more or less current.