There were "copycat" Toynbee tilers in the mid-to-late 2000's. I suspect a reasonable number of the tiles in more remote locations are not the work of the original tiler.

Case in point: I found a "Toynbee Tile" in San Francisco on Geary west of Union Square in 2007. I posted it on my blog the day we found it, and there was discussion in a message board about it the next day: https://web.archive.org/web/20080325024107/http://resurrectd...