Read this section of the US Constitution:
"The Congress shall have Power...To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries..."
Translation: Congress is responsible for the enforcement of patents and copyrighted material. Therefore, it has the right and ability to create copyright law for all forms of entertainment. Of course, there is also the case of fair use, where individuals and non-profits use copyrighted material for producing other forms of creative art. Thus it is the discretion of both the legal system, the supposed "pirate" and the original artist to determine whether fair use was or was not abused.
Extra Credits said it best (at least for video games) when they said that if you have relatively easy access to the material, then you should not pirate, but if its absolutely impossible to buy or access the material legally, then it is somewhat acceptable to pirate.
And finally, keep in mind that technically OCR is a non-profit, thus as long as we do not publish works that border "copy-paste" material, that the game companies have confidence in and admiration for our work, and that we are (most likely) protected under fair use, OCR is almost immune from prospective lawsuits.