just a WAG, but could success of this “teaching” be based precisely on teaching sales techniques to people who are not familiar with them and stand to benefit from the knowledge? If that’s correct, maybe that’s not the best way to teach them, and maybe they also teach a whole lot of useless BS, but students might still derive some benefit from the tidbits of useful knowledge in the curriculum hence helping with repeat customers and word of mouth marketing.
Cite that any of the groups you just named uses NLP?
The methods to define and market NLP, along with the responses to questions raised by scientific testing, are exactly the same as those used for other pseudo-science theories, and flat out fraud. It’s reasonable to assume that the NLP advocates would follow a different path if their theories were actually effective. Although EMDR, mentioned by njtt, is controversial, it is at least subject to continued objective investigation based on some measureable record of success.
As for Darren Brown, everything he does in his act could be accomplished through techniques used by entertainers and frauds through the ages. Whether he uses NLP or not is irrelevant.
Derren Brown doesn’t use NLP, nor does he even claim to use NLP. As an entertainer, he does often give intentionally misleading descriptions of the methods he uses to accomplish his magic tricks, but he neither claims to use nor actually uses NLP for any of it. There is no relation between Derren Brown’s act and NLP, except insofar as quite a lot of people seem to have bought in to the mistaken rumor that there is some connection.