Quote from akuma_river
Technically speaking translating a work and editing it and cleaning it can fit under Fair Use by art and literary means as it is a TRANSFORMATIVE work. People just argue on how much you need to change a source material for it to no longer be qualified under stringent 'copyright' and fits under Fair Use. The fact that no one is charging for the work can also be said to follow under education means...since the internet is technically an international library.
Any and all chance of a Fair Use claim is thrown out the window as soon as the scanlating groups release the full manga art.
If it was purely the transcription, then the court may find in your favour. There is no grey area when it comes to redistributing the entirety of the original work.
I wish people would stop pretending about the legality of Scanlation.