This page is such interesting reading, especially the patterns that emerge when authors talk about the reasons why they changed their minds about fic, why they allow it but don’t read it, and so on. Several authors (Ellen Kushner, Poppy Z. Brite) mention that they once believed fic endangered their copyright in their works, but have since learned that that fear is false. Others, like Orson Scott Card and Jennifer Roberson, still seem to be clinging to it to some degree. Many more authors (Sarah Rees Brennan, N.K. Jemisin, Marjorie M. Liu, Diana Peterfreund, Kaja & Phil Foglio, Katherine Kurtz) mention that they don’t read fic for legal reasons, Many others mention that they read and write fic, or sometimes even comment on it.
Most of the sources cited for the authors’ comments seem to be fairly recent. It’s interesting to see that even today, there’s so much variety in how pro authors understand the relation between fanworks and copyright law. You’d expect that there would be at least some sort of professional consensus by now, but it seems like echoes of the confusion caused by the Marion Zimmer Bradley Contraband incident are still around.