pro camera skintones

I was watching this youTube thread comparing the Nikon D3S and the 1D Mark IV:

http://www.youtube.com​/watch?v=vkg7pAxi4gE

While they never mentioned this in their comparisons, I noticed the video capture of the Nikon D3S photos showed the model's skintones as unnaturally warm while the Canon 1DmarkIV showed the model's skintones as unnaturally cool. Both were very obvious. The video itself had a more natural skintone of the model.

I also remember a thread here comparing the 1DsIII to the 1DIV where a poster felt that the 1DsIII skintones were more natural looking.

I'm curious about this and would like to better understand these differences and why they seem to be so obvious (it's not very subjective in the video).

If both cameras were using Automatic White Balance ("AWB" in Canon lingo), those results do not surprise me one little bit. AWB in my 20D is wrong more often than it is right in anything but open daylight and even then I don't trust it.