I don't mean to speak for James, but what he is saying is that the Panasonic Blu-ray player pulls both streams off the 3D Blu-ray disc (both the left eye view and the derived right eye view, both full resolution 1920x1080), then tosses away half the vertical resolution so that it can combine the two resulting 960x1080 images into a single 1920x1080 frame. That frame, which appears in 2D as two squeezed images, side by side, can be examined for any traces of crosstalk. If you see none, then it means the no crosstalk exists in the encoded 3D image.
I never believed that would be the case anyway, but James' technique demonstrates clearly that MVC encoding does not compromise the right eye view with crosstalk. The crosstalk culprit, as we all thought, is either the glasses or the display, or both.