It would appear that plumbers from the CC forum prefer customers who do not ask probing questions.
Customers who do not expect legible, relevant documentation
Customers who expect the tradesperson to persistently push one product purely out of bigotry.
Customers who do not expect the registration to be properly completed.
Customers who are not bothered about the lack of references.
Customers who are happy to do their own research when the answers to their questions are rebuffed with inanities.
Customers who are content with vague references to something that was heard on the radio.
Customers who are happy when the tradesperson resorts to clown impressions when faced with difficulties, especially difficulties of their own making.
Customers that will accept copies of previous documentation even if it is not relevant.
Customers who accept persistent lies instead of fair and just answers.
Have you had any work done by any of the plumbers on here?
If you have not, then I would suggest you have no proof of the above at all