There are no professionals in the carpet cleaning trade and nobody on here can provide a reliable source or quote that will prove otherwise.
Next you'll be saying window cleaning is a profession, or emptying bins. They are not professions and you cannot by definition provide a professional service.
Some people on here seem to think that because they've taken a 3 day course they are suddenly elevated in stature above others who have simply learned how to do the job themselves.
The bottom line is, it is unlikely that the forum is populated by very many cowboys or "splash and dash" merchants as those guys would have no interest in discussing serious matters about cleaning carpets. Probably every member here will have some piece of knowledge that the majority of the others don't, that's the way I see it and that's why I joined.