Joe:
Question 1:
I see nothing wrong with QUALIFIED individuals "selling" training products. Quite a few inspectors & contractors in this area also "work" as certified instructors within there various fields of expertise. (Electrical, plumbing, building, fire prevention, etc.) As to them "selling"; some offer various Code related texts, at fair pricing.
Question 2:
Personally, anyone should have qualifications in any subject they are "teaching". As to selling shoes, they can offer there talents to people seeking that knowledge; not "brain surgery". We provide electrical maintenance to a national chain of sporting goods and shoes stores, my favorite line to the DIY store people is "I don't sell shoes; you should not do electrical work".
Question 3:
Our supply houses give us what we ask for. The DIY's that frequent there ask all the questions, and in MHO, get the riht replies, ususlly "call a licensed electrician". The big box stores are the place that give "advice"; sometimes good, sometimes bad, but that's another thread. The professional supply houses (Cooper, Graybar, etc.) usually deal with pros, and the DIY's are the ones that "delay" prompt counter service. IMHO, there is nothing wrong with steering someone in the right direction, but if they don't know what they want, how much "help" can anyone give them.
John
