A bit OT, but I've always wanted "Prefer HD" to mean ""Prefer the HD broadcast if it's from HD source material, not just upscaled SD".
Nice trick if you can find it.
I also make an observation on Nines HD an SD simulcast for the cricket.
Either my eyes have gone blurry the SD broadcast was of a lower definition than they usually broadcast.
However when I looked at the HD channel via the Yellow RCA socket of the PVR (i.e. HD downscaled to SD locally by the PVR) the image was much clearer than the Nine SD broadcast.
The HD image was definitely superior to the SD, however I suspect a bit of marketing was involved. i.e. degrade the SD image a bit to make the HD look better.