True but this is way cooler. Remember the multi-user-by-face-detection rumor before the 1st iPad unveiled?
If Apple were that interested in supporting multi-user support for their devices, they wouldn't do so at a cost to them, if it can be done with software methods. Yes it is cool to scan a users face or fingerprint, but there are better, cheaper ways of achieving multi-user support.
My idea on how to implement facial recognition correctly was to use a kinect like system that emits an infrared light on to the face - which removes the photo bypass method for what it's worth. I think this could be the future idea behind technology such as Leap (www.leapmotion.com) though.