From Fan History Wiki

People and organizations threatened with legal action by Heidi8

[edit] Timeline

• By January 2001, Cassandra Claire had already been plagiarized at least once on FanFiction.Net and had been concerned about people writing unauthorized sequels for her work. Heidi8 had also referenced these issues. Cassandra Claire and Heidi were both, at this point, also actively engaging in plagiarism themselves. [1][2] It is thus that the disclaimers from this period should be looked at, at least in regards to Cassandra Claire. stellabymoor at fwgreatesthits [3] has a Cassandra Claire disclaimer which she claims to date from January 9, 2001 which first appeared in Draco Sinister 4. The disclaimer says:

Disclaimer: I’ve mentioned all this before, but I suppose it bears repeating: none of the characters are mine, they all belong to JK Rowling (obviously) and Draco’s & others’ lines come from many sources: some are made up, some inspired by many sources, including but not limited to : Buffy the Vampire Slayer, Forever Knight, Due South, the X-Files, Woody Allen, the Handbook for Evil Overlords, obscure British sitcoms, Monty Python, Shakespeare, and I could go on and on, but rest assured that no maliciousness is intended and I am making not one cent (even more obviously!) off writing this, nor would I even want to. If you want to play spot-the-quote, feel free! More fun for everyone. [4]

This was the first use of a disclaimer in a chapter by Cassandra Claire. Prior to the January 9, 2001 disclaimer for Draco Sinister chapter 4, stellabymoor indicates no disclaimers for the use of quotes appeared in chapters of the Draco Trilogy. [5] Another disclaimer for the trilogy as posted to FanFiction.Net is dated January 19, 2001. It was for Draco Sinister 9 and read as:

Credit for the inspiration for this conception of the wizarding afterlife goes to a book called The Secret Country, alas, I no longer recall who wrote it. [6]

This disclaimer for chapter 9's use of Pamela Dean's work without credit was the reason FanFiction.Net eventually black listed Cassandra Claire. Cassandra Claire's knowledge of plagiarism being a black listing offense was clearly known due to both Heidi's post dated January 3, 2001 and the incident where Cassandra Claire was plagiarized in September 2000.