Hmm, all LucasFilm/Arts games have removed code protections and that on every platform. You can play the Amiga version of Loom without the code protection and as far as I know there is no version of Amiga Loom without it. Maybe the authors have a special agreement with LucasArts to remove the code protection and it's still in there for other companies.
Edit : Found the wiki about the code protection bypass : http://wiki.scummvm.org/index.php/Us..._Using_ScummVM
(scroll down a bit)
Interesting fact is that also Indiana Jones (both Last Crusade and Fate of Atlantis) don't have the copy protection anymore...