PS-X homebrew cdrom master with Wobble Groove data

If anyone could please clarify a certian something i happend to come across - if i understood properly everything that was told in this thread so far, what this guy had been talking about: http://www.baetzler.de/vidgames/psx_cd_faq.html ..is probably nonscense right?

If the license letters (e.g. the wobble) are recorded somewhere in the ToC area of the CD, the EDC/ECC checksum check doesn't even necessarily apply here right?

Please do correct me if i'm wrong.

 

At one point Connectix Virtual Station used the checksum to detect copies, but they eventually had to take that change out. It appears that only some games were like it and it was likely a mastering error.