I still don't know it. I've been active or semi-active in fanzine publication for over fifty years, and this is the first time I've heard about it. Such mandatory submission has been in effect (and probably still is) in the U.K. and Canada, but in the U.S. it applied (and, I think, still does) only when registering something for copyright -- which only one amateur publsher I know of (out of hundreds) has ever bothered to do.