Microsoft has filed for a Kinect-related patent, and it’s a doozy of an application. The abstract describes a camera-based system that would monitor the number of viewers in a room and check to see if the number of occupants exceeded a certain threshold set by the content provider. If there are too many warm bodies present, the device owner would be prompted to purchase a license for a greater number of viewers.

No, really. It’s that blunt. From the abstract: “The users consuming the content on a display device are monitored so that if the number of user-views licensed is exceeded, remedial action may be taken.”

It’s refreshing to see Microsoft eschewing its play-nice-with-everyone approach to business for some old-fashioned, straight-up evil. The patent’s various claims can endow a device with a limited number of performances in a given period of time, a limited number of users allowed to view such performances, and the continuous monitoring of viewers during those performances. It also covers the determination of “when performance of the content to an identified user exceeds a threshold.”

The really interesting thing about this patent is that it suggests that copyright holders are allowed to govern performances in otherwise private dwellings. The application describes how the patent could be applied to head-mounted devices, large screens, gaming and media products, computers, and even mobile phones. Clearly, this isn’t just a method for cracking down on illicit big-screen viewings of movies and television that might plausibly be called a public performance.

Perhaps we shouldn’t be surprised. This is the logical extension of the “you only buy a license” philosophy that rules the content provider universe. Microsoft’s misstep here is in filing for a patent on devices that can only provide a personal viewing experience. Getting 50 people together to watch a movie on someone’s 84-inch television may indeed count as a public performance, as far as copyright law is concerned. Two people watching a movie on a 10-inch iPad, on the other hand, isn’t quite the same thing. MS’s new patent covers both scenarios.

Recent developments in US copyright law could leave a patent like this without much of a bite. Last summer, Judge Posner on the 7th Circuit Court of Appeals struck down a lower court ruling that claimed embedding a video in a website qualified as copyright infringement. In the decision, Posner held that viewing an uploaded video does not infringe on copyright law’s reproductive or distributive rights. The law, he wrote, is unclear on whether or not the act of viewing content infringes on a copyright holder’s performance rights.

This question could have a significant impact on whether or not copyright holders spring for systems like the one Microsoft is trying to patent. If viewing a video online constitutes a performance infringement, rightsholders could mandate a user-detection scheme under the auspices of the DMCA. If it doesn’t, no electronics company on Earth will want to touch the idea for fear of a consumer backlash.

Now read: Why I pirate