1) How cults recruit and retain members. How to recognized it and tell them to fuck off before they get their hooks in you. Ditto MLMs, et c.
2) How to lie with statistics.
3) All the stuff from Cialdini’s Persuasion
I intend to give my kids such a course at home, since schools don’t do it.
Really, I think schools would have trouble adding such a course. I think too many families are involved in one part or another of all that, and would agitate to end it.