@MusedMoose - I'm fairly certain you're wrong about the legal issues surrounding fanfic. Strictly speaking, fanfic authors have no rights to their derivative works. Fanfic is usually tolerated by the original work's copyright holder because it presents no harm, but there's a reason you only see it circulated online; it can't be commercially distributed.

If you look at the infamous Harry Potter Lexicon case, you'll see that this doesn't only apply to fan creations that are told in a fictive mode, but also to speculative materials like timelines and encyclopedias that conflict with what the rights holder also wishes to produce. (This was a case where Steve Vander Ark unwisely attempted to publish the most prominent online fan compendium of Potter material in printed form, and his publisher, RDR Books, was sued for doing so. The fact that the fan timeline on the site was likely the source for the timelines on the official Warner Bros. DVDs had no bearing on the law.)

In fact, one of the persistent worries of fanfic communities (look up the one that has branded itself the "Organization for Transformative Works") is that there ISN'T any legal protection for fanfic (and for good reasons, I might add). If an author steals your fanfic you can go ahead and sue, but you aren't going to win. Otherwise there would be an unreasonable expectation on the part of the author to prove the kind of thing you suggest - a total ignorance of the fanfic and speculation going on. Thankfully, that isn't the case.

I'm not sure where you got your Mercedes Lackey example, but Lackey began as a fanfic writer herself, and has been one of the few authors to grant permission for its noncommercial distribution via Creative Commons.