Thanks BDAqua,
I think it might be possible, but I fail to see how it might be easy unless it was my wife who already knows how to unlock the basement door. We do have several security cameras around, so it might not be worth it for someone to break in, hide a recording device or a microphone. Then trigger that device to broadcast, while they were near the basement door. It would be much simpler to break the window beside the door and reach in and unlock it. If Apple would allow me to sign away my rights to sue in order to use voice authentication via Siri for specific situations I would gladly do that for the basement door situation.