you're right. nobody is going to buy it now because the guy they hired used canon and clearly that makes the d800 no good.
It's not that, it's a combination of the footage implying it was taken by the D800, and also the possible copyright infringement:
TSO Photography (who did some of the shots from that clip):
"A bit surprised to see Nikon using some of my video clips in the world launch of the Nikon D800 camera in Bangkok on the 7th without contacting me. Especially since Canon is one of my sponsors, and I use a 5DII."