I'm pretty sure the generations in development have video cameras and microphones (to allow you to cough wave your hands or speak to change channels, of course). That same platform also has ISM radios in monitoring mode so that they can see what devices are present and obtain rough positioning data. So they'll know when you get home based on your phone mac appearing, and how many people are on the couch and who they are.

here is the video recognition stb patent application that includes a number of eye openers:

http://www.freepatentsonline.com/20130042270.pdf