The fundamental problem with their Lego trading game (and the original Legotown) is that they assume capitalism involves a fixed amount of resources that can only be traded. In reality, the resources are constantly growing. If it was really a fixed-resource system, it would always end like Monopoly, with one person owning everything, or owning enough to always be in power at the least.

All it takes is a second to stop and realize that wealth is created, not taken. If it was all really taken, then where in the heck did we take it from? (I mean we as in the whole world.) The world is immensely more wealthy than it was a thousand years ago, and all that wealth was created by the hard work of all those generations. Surely all the wealth creation done by startups is evidence of that.

I think this is generally an economic misunderstanding that a lot of people have. To them, it's "Every dollar Bill Gates has is a dollar less for everyone else, so that is unfair." In fact, PG made this argument much better than I can, here: http://www.paulgraham.com/wealth.html

That said, I did really enjoy how these teachers approached the art of teaching children. Challenging the children to examine and modify their own worldviews seems infinitely more effective than preaching to them about 'the right way.'