Certainly, from what I can gather, Sigma is adding it to the SDKs of (some of) their chips.
But, I'd have to hazard a guess that that's because the chips are also sold for use in commercial BluRay players, where Cinavia detection is now required under AACS.
As others have pointed out before I ever did, it seems highly counter-productive for digital media player manufacturers to enable the detection, unless they become obligated to.
I guess when the 8910-based devices start showing up later this year, we can see how many of them enabled the Cinavia. The Dune Pro might have to, for the optical drive module, but other players would be a significant test of whether the capabilities are actually utilized or ignored.
As far as I can still tell, Cinavia has not been added to the 865x SDK (because the line was never designed for BluRay players to utilize), so WD would seem to be _ unable _ to add it to the Live/Live Plus/Live Hub at this point in time. The WDTV SMP is another matter... I can't find any solid confirmation whether the 8670 SDK has Cinavia or not, yet.
From what I can see, Sigma lists:
as the current SMP chips for BluRay players... so those SDKs would need Cinavia -- it seems, according to NetGear, that it isn't in the 8642 SDK yet.
as the current SMP chips for Media Players... The 8910 and the 864x would need Cinavia, because they're also intended for BR players, but there's no indication the 867x and 865x lines would need Cinavia added to the SDK, since they are not intended for BR use.