It's an interesting way to release Shedinja. On the one hand, could've been done in a much more annoying way (e.g. "When you evolve Nincada, there's a 0.01% chance you'll get Shedinja too! Get evolving, trainers!"). On the other hand, it could've been more imaginative, and does this mean Shedinja will be unobtainable (at least for a while) after November?
Also curious what (if anything) they're doing to handle Shedinja's unique properties. Or maybe they're just taking the lazy approach and doing nothing...
