Well, I don't think AnyDVD is trying to claim they let you watch non-HDCP protected content without HDCP hardware... "Buy our product, it'll let you do what you could do anyway" isn't really a very good marketing slogan. It lets you watch HD-DVDs (which are all HDCP protected AFIK) and BRDs (which are also all HDCP protected, also AFIK).
I reread your post MrCrispy... I see what you're saying now, I think. You're saying that AnyDVD HD may run into additional problems if you have HDCP enabled hardware, like an HDCP enabled video card. Right?
I definitely don't know enough about HDCP to make a guess as to whether this would actually be the case, but I'd guess there would be many posts about it on the Slysoft forum. I took a quick look, but I didn't see any. I unfortunately don't have ANY HD computer hardware, so I can't come close to testing the software myself.