"Regarding teaching, running a school is much easier than playing the system and you have regular income. It also may be the only option for good advantage players after their faces get in the player database."

That's not the only option. Some of those who have run schools for advantage blackjack play have been double-dippers. They teach people how to beat the game, then they hire themselves out to the casinos as security consultants. They tell/show the casinos how to spot players using the techniques these guys taught their own students. I seem to recall reading Sanford Wong was one of the double-dippers. ...doesn't seem quite fair to me.