Work Place Privacy in California
Employees in California have a right to privacy says the California Supreme Court in Hernandez v. Hillsides. But, that right is limited and defined by the circumstances. In some cases, companies are allowed to monitor employees with hidden cameras or other methods, but employees are entitled to notice of the monitoring and the company will need a good reason to monitor. For example, in the Herandez case, the company placed a hidden camera in a workroom because they were trying to identify an employee who was watching porn on a computer in a facility that cared for abused children. The company had a strong reason to use the hidden the camera.
They key point is that employees do have a right to privacy, but that right can be compromised if the company has a legitimate reason. Also, companies should notify employees of potential monitoring in the company policy manual or other posting locations. But, if a company does not notify employees of the monitoring and does not have a good reason, then employees may be able to sue the company for invasion of privacy.
For a thorough review of Hernandez from an employer's perspective, see the Labor Employment Blog by Sheppard Mullin.