In one embodiment the present invention includes a system for identifying an unauthorized display of content. The system includes a preprocessor, an inserter, an observation device, and a subscriber information device. The preprocessor device preprocesses the content for subsequent insertion of semi-visible information. The inserter device inserts a semi-visible watermark into the content as having been preprocessed by the preprocessor device. The semi-visible watermark corresponds to a subscriber identifier. The observation device executes processing, including receiving an input from an observer that observes a display of the content that includes the semi-visible watermark. The input corresponds to the semi visible watermark. The processing further includes processing the input to generate an input result. The subscriber information device stores subscriber identifiers and identifies a particular subscriber by comparing the input result and the subscriber identifiers.