The most common way employers invade their employees’ privacy is to intrude on their seclusion, solitude, or private affairs.  If the employer has a legitimate reason for the intrusion (e.g., to investigate theft or suspected illegal conduct), an intrusion reasonably limited to serve these legitimate interests is probably legal.  Any company considering potentially intrusive action should notify employees in advance of the intended intrusion, to eliminate employees’ expectations of privacy.  Additionally, a well-written policy can assist in defending the search against any claimed invasion of privacy.  An experienced employment attorney can provide advice as to whether a proposed action might be overly intrusive.