Well, someone designed a sd-card cable for DC (JJ1ODM) and many people ahve implemented it in their console. And there's also a way to dump most gd-rom with a specific dvd-drive (Lite-On Ltd-165H), which I've made a french tutorial on:
[Windows] Ripper un GD-Rom avec le lecteur de son PC :: DreamAgain
But the goal here isn't to check if the users can do dirty hardware hacks to their DC, it's simply to check with a relatively good protection algorithm if they own an ORIGINAL gd-rom of the game that's being translated. Only the low-density region of the original GD-ROM in a cd-rom drive will probably be checked. So as many people as possible can use the translation!
Cheers,
FG