It's hard to tell. I think they would be very stupid to so, shooting on the scene that is their clientel, but you never know with the big companies, they can be surprisingly stupid. And I'm a bit worried for them going after the big archive sites like AO3. It's not that fanfic would disappear but it would have to go more underground and hide behind friends locks and so on.

While I rather like the idea that people can live off their writing I think it might be better to stick with changing the names and calling it original. This way, the writers have far more rights and the fanfic scene stays the fun experimental scene it is.