After reading the story at the beginning, I thought "huh, this teacher seems rather low-level for a teacher". I also thought that back when I was first getting into LW, a depiction of that level as the highest level would not have encouraged me to explore further.

I was more pleased with the bit at the end.

At some point, it might be worth making a few versions of this story which illustrate some of the trickier techniques, with the urn lady trying exploit specific biases. If a short story like that illustrated a bias well enough to trick the reader right up until the reveal, and the reveal were written so that the reader could believably learn to think in such a way as to catch it, I think that would really help convince newcomers that there's material here worth studying.