HD DVD players operate in one of two modes depending on the disc they are running: Fulltrust and restricted modes. The mode is selected at player start and does not change. After all the hand waving is done, Fulltrust == AACS, restricted is what you get otherwise. Some of the restrictions are for good reasons, networks are disabled to prevent your HD DVD player from becoming some ones zombie, no persistent memory access is permitted to avoid malicious wearing out of the flash memory (most flash is spec'ed for only a million writes, or so). Others seem intended to keep you from having too much fun (like font specifications). Of course, a well enhanced VLC would probably ignore these restrictions.