A method and system to warn the user in the event of potential confidential document security violations. The method includes using a computer, electronically embedding a digital marker in an electronic document to create a marked document; storing the document on a non-removable non-transitory computer readable medium of the computer; upon a request for transmission of the marked document from the computer or for copying the marked document to a removable non-transitory computer readable medium, determining that the marked document contains the digital marker and displaying a warning on a display unit of the computer of the request based on the marked document containing the digital marker; and allowing the transmission or the copying only upon approval of release of the marked document by a human user of the computer.