Unlike the law, psychology, and even trades (e.g. plumbing, electrical), there is no regulation in the training industry. There is no central licencing agency, or even licencing requirements at the state or provincial level. In fact, anyone can call themselves a trainer, and operate as a trainer. Since there is neither regulation, or certification requirements, that keeps training as a semi-profession, where, oddly enough, it's easier to become a trainer than it is a plumber.
Of course that's good if you want to be a a trainer. But it also has a downside, since it makes it hard for customers to sift through trainers who have no experience or qualifications and those that do. It also contributes to conveying an image about training that is less than flattering, since there are many poor, flaky, or off the wall trainers.
The issue of regulation, in any field is complex, with pros and cons as to whether regulation is good or bad, and of course, it often depends on a) how it might be done, and b) where one sits in one's career, and c) one's own background and qualifications.
An Important Distinction
I hold an MA in Psychology and finished all PH.D coursework, but am not a licenced Psychologist. Early in my career, I used the word "psychological" in my marketing material, being careful NOT to make any claims as to being a Psychologist. I was surprised to be contacted by the provincial governing body and informed that I could not continue to use the word "psychological". Someone had filed a complaint. We ended up complying rather than pushing the issue.
Trainers should know that while training is unregulated, it is possible to stumble close to, or into areas that ARE regulated, and that can be dangerous. Psychology is regulated, so that there are law/rules about qualifications, licensing, ethics, and education usually administered by a state or provincial body or association.
While this shouldn't apply to trainers, it sometimes does. You may not be able to use the words psychology or psychological in your marketing material. More importantly, you may not (at the discretion of the governing body) practice psychology without a licence. If your work starts to become therapy, even if it's unintended, you can, at least theoretically, be challenged and even charged.
It's not a likely scenario, but more and more, governments are looking at additional legislation (under the concept of consumer protection) to prevent unskilled people from doing therapy like work unless they are licenced. So far, it seems that the field of COACHING is the main target for new legislation, but it is important for trainers to stay clear of doing therapy without qualification.