Hidden Cameras in the Workplace?

Reported from law.com (full article here)

Suspecting someone was viewing pornographic Web sites on a company computer after hours, the executive director of a Los Angeles-area center for abused children set up a secret video system in 2002 to catch the culprit.

No one was apprehended, but the two women who shared the locked office that was placed under surveillance sued for invasion of privacy -- even though the only images ever captured were shots of an empty desk and their boss setting up the camera.

That was what the California Supreme Court had to work with Wednesday during oral arguments in Hernandez v. Hillsides Inc., S147552: Does the mere attempt to videotape an individual qualify as an invasion of privacy or must there be an actual intrusion -- such as the taping of an innocent person changing clothes -- for liability to come into play?