BTW, the HDCD license that the manufacturer needs in order to sell a player with an HDCD decoder requires that the player have an indicator for HDCD disks. It also requires that the level of non HDCD disks be 6db lower than HDCD disks. Some manufacturers put a defeat switch inside the player for this gain reduction - it doesn't violate the license if the end user disables the gain reduction.
For a long time Pacific Microsonics would not grant a license for a software implementation of HDCD (I.e. Wadia, Theta, Krell, etc) - you had to buy their decoder chip (PMD-100 or PMD-200). I think that stance has shifted since Microsoft bought them.