If I recall correctly, some of the copy protection schemes are designed to defeat even that one.

It is said to work by inserting bogus frames into the S/PDIF stream, but NOT to the playback hardware. That said, it would seem possible to hijack the I2S, Sony, or whatever internal digital lines feeding the DAC of the CD player and then connecting to something such as the S/PDIF boards above. Maybe not, but to me it would make sense that if the CD player's DAC is not seeing the bogus frames, then another device fed by the same digital lines would also be oblivious to them as well.

Stu