Law.com: Workplace Computer Off-Limits?
A New Haven, Conn., criminal defense lawyer wants the state Supreme Court to recognize that employees have some expectation of privacy when it comes to their workplace computers — even if the material they are viewing or downloading is child pornography.
See also: Leventhal v. Knapek, where the Second Circuit ruled that a public employee has a reasonable expectation of privacy for his workplace computer and that a warrantless search of that computer violates the Fourth Amendment.
Even if employees have a reasonable expectation of privacy in their workplace computer, downloading a library of child pornography is still a bad idea.