I don't think I have a single HDCD title in my collection, so it's not something I think about much. None of my various CD players have included HDCD support, and none of my receivers or processors have either.

HDCD predates DRM issues associated with DVD-Audio and SACD, and since it is an extension of the Audio CD format (which dates back a long way now) it would be very difficult to allow any sort of DRM restrictions without creating a product that violated the audo CD format requirements.