You thought you knew everything there was to know about the Nexus 7? Well, you thought wrong. A curious owner of the device started doing what any totally rational person does with a brand-new tablet: expose it to magnetic forces. The results yielded an as-yet hidden feature in the Nexus 7, in the form a magnetic smart cover sensor. Simply take a magnet and put it up against the front or back of your Nexus 7 along the bottom left-hand side while in portrait mode with the display on, and you can see the effect for yourself. Or, you could just watch this video of our tipster doing it:
While Google does sell covers for the Nexus 7, it's unclear if they support this feature (though ASUS does call it a "smart cover" here). It would be a little odd, given they open from right to left, and the magnetic sensor is on the left side. Still, it's entirely possible. We've confirmed it on our own I/O Nexus 7s, so this is definitely legit.
The iPad has its Smart Cover since the iPad 2, and it seems a similar functionality will be present on Microsoft's Surface tablet. Apple does have a patent for its Smart Cover magnetic system, but it's not a very broad one.
Reviewing Apple's patent on its Smart Cover, it seems to be rather narrowly tailored in form and function for the Smart Cover and iPad mechanism specifically, and focuses more on its ability to latch onto the host device rather than turning its display off and on. There is talk of "useful functionality" being added by the cover, but based on the patent language, that seems to still fall only within Apple's particular design and mechanism - not in general. So, it's entirely possible (even likely) Google and ASUS's design here isn't sufficiently similar to infringe - but we don't know. That's the kind of question that only a teardown, an engineer, and a patent lawyer can fully answer.