Content is encoded with a watermark that associates it with a particular consumer. When presented for playback, the rendering equipment examines the watermark to confirm that the consumer with whom the content is associated, is also the consumer with whom the equipment is associated. If there is no watermark—or if the watermark is associated with a different consumer, then playback is refused. The equipment also desirably checks whether the content has a second watermark (or even a very feeble remnant thereof), indicating that the content has been derived from content earlier provided to a different consumer. If so, playback is again refused. Thus, this embodiment will refuse to play if there is no watermark; if there is one watermark not associated with the proprietor of the equipment; or if there are two or more watermarks.