Really, now? News to me and everyone else.
The 0-spell chiv books actually date from the first days of AoS, and the introduction of the Chivalry skill, from a bug. LONG before the ML dog/changeling dupes. In fact, the 3 I have I got from an IDOC before the release of SE, let alone ML.
In fact, the idea that one could create a zero-spell chiv book with the dog/changeling dupes is something I'd never even heard of before, so I doubt anyone was doing it in large amounts - if it was even possible.