A judge would clearly believe Bitcoins have value, as would any reasonable man after seeing MtGox, so securities laws would apply if you issued shares denominated in BTC. End of story.
Did I say bitcoin has no value? Where? Of course, they have value. So does everything that is surrounding us has value for somebody. Does that mean security laws apply for everything that is surrounding us?
So does my email signed with my private key has value. But... not for the judge! As the judge doesn't have the public key to unlock it! End of story.