Apparently on the DMZ, they have created a computer program to leverage the Kinect to detect people trying to cross the border into South Korea. They mainly use it to differentiate between humans and animals at specific spots. Singapore also uses it to detect border crossings and found that it helps see people behind dark tinted glass and in low-light conditions (more on that here.)
The latest version of the Kinect features 3D depth sensors, "Active IR," and facial recognition. Microsoft also says it can detect levels of force applied to an action and detect a human heart rate. All this seems like it would be handy for differentiating humans and animals.
Here a demo of the latest Kinect features:
Does anyone see this as being something promising for security applications? There are a few hacks online here and here, but I haven't found any other serious applications like Singapore or South Korea. It seems like it could be valuable if someone figured out how to integrate it with security systems.