> It seems like a no-brainer to have people learn on hammers

When I was young I attended a karate dojo. One interaction that always stayed with me was when someone asked why the guy with a black belt could do the katas differently.

The sensei answered that when learning, your task is to learn to do the katas perfectly. As a black belt, you have amply demonstrated that, so now your task is to be creative and build on the foundations.

I liked that answer, it applies to everything. Learn the basics before you are allowed to question them. After that, you must question them.

thats an awesome example

giving ai to children without limits is like giving them leg-braces or wheelchairs; they'll get used to it and never learn to walk or run by themselves much less karate... they'll be cripples from the start.