Under current law, copyright applies to any creative work, regardless of publication status. This leads to abominations such as Disney's Vault, intentionally restricting access to a work that is part of the public consciousness.

In my ideal world, if the source code is not placed under escrow and tested to result in the distributed binary, then there would be no monopoly given to that binary. Anybody is allowed to copy it to the fullest extent that they are able to.