Now let’s respond to the second concern, the risk of doing harm to the client. I know of a number of specific examples of people who have been seriously harmed by both Licensed professionals and by NLP Practitioners, so the risk is real.
Firstly, if someone thinks that the NLP toolbox is less effective than that of licensed professionals, you can point out that the danger must also be proportionately less, since fewer skills means less ability to influence someone. Then you only have to deal with the ethics of charging people money for ineffective therapy.
Assuming that Practitioners have a more effective toolbox, how about the danger that this more powerful toolbox might pose in the hands of someone with little experience? More power to help someone change does not specify the direction or usefulness of change.
It is MUCH easier to help someone change in a way that is useful and congruent with their wishes and outcomes. It takes much greater skill (or bravado, or coercion) to overwhelm a person's natural protective responses to unecological change. With appropriate frames, I believe that new Practitioners with minimal experience can significantly help a lot of people, while at the same time protecting clients from harm.
What are those frames? Primarily...
These are frames which we have always built in to all our trainings, in every way we could think of, and over and over again. There are a number of NLP training programs that do not emphasize, or even mention, them, or that offer quite different frames. However, given these frames, I believe it is very hard to harm anyone. The vast majority of the harm that I have observed has resulted from ignoring them, and I have seen far more of this resulting from the work of professional licensed psychotherapists than I have from NLP Practitioners.