Quoting the pab3d1_1.readme from Aminet:
(...)
" * Skips the codebook protection (With FULL PERMISSION from Team17)"
(..)
So at least for ab3d you can legally get rid of the protection.
BTW I've never seen the full version of this game on Aminet. Maybe you were referring to the ab3d2 source, Redrumloa?
Also, as the souce code is available, it means that also the full game has become freeware??
Varthall