David wins a new Lamborghini immediately upon receipt of 300,000 Loonies Sales Tax.

Forrest Mims III predates current surveillance techniques by decades but suggested training a IR laser beam on a large widow. Any voices within would modulate the laser beam and would be readily demodulated by the listener/receiver. A large glass window provides an excellent "timpanic membrane". The very heart of today's audio "bugging" devices.

Good on ya, David!