Based on what they have said in interviews, I have a feeling that is exactly what they are doing.
My guess is that they combine a number of signals to do the tracking, and when those signals start to disagree too much they've prioritized some signals over others. That could include things like how your eyes are tracking and other physiological signals, not just the accelerometer and various cameras.
My guess is that they combine a number of signals to do the tracking, and when those signals start to disagree too much they've prioritized some signals over others. That could include things like how your eyes are tracking and other physiological signals, not just the accelerometer and various cameras.