Help this fella see the light?

I was just reading about RFID, and was wondering if it's possible to use RFID to figure out what room a person is in. That way the lights could activate and deactivate as a person steps through the house, as well as many other things. You can read the entire message here. But believe me, his phrase 'as well as many other things' is fully loaded. He may be more interested in being in the dark? I learned about the RFID system in an issue of Popular Science. It said "if the system detected you and your wife in the same room, the lights could dim and the stereo could kick on the mood music (after it confirmed the kids were gone)." Man, I have to start reading Popular Science again.