For GPL code, as long as they provide the modified and complete source code along with their own versions, everything should be fine. Artwork and other works n

For GPL code, as long as they provide the modified and complete source code along with their own versions, everything should be fine. Artwork and other works not govered by GPL is of course another issue, however I believe that in most cases those are often licensed similarly to GPL (GNU Free Documentation License?). Of course, it might be that they didn't include the source code or forgot to attribute the original authors. At least that would constitute ripping.