A mate of mine has his own window and carpet cleaning company in london, he was doing a clean on a building site and got asked to have his carpet cleaner pat tested. Him and his wife went and done a course for a day, brought the cheapest pat tester they could find, now they do that on there own equipment and as an extra. Hes always been a window cleaner has not got any experience at all, but still said the course was an absolute breeze, a waste of money was his words. He learnt more reading the instruction manual that came with the PAT tester than on the course.
Whats funny though is hes scored some large nationwide contracts for the PAT testing all ready off the back of this qualification...
Well there are some intelligent people out there ! but that doesn't mean its a free for all. As I said the Group 4 example is only one and the reason for failure had more to do with attitude towards their employer rather than their own personal intelligence.
I think on the whole, Its not about using instruments and printing out a pass or fail ticket, but is how the results are interpreted.
There is a good reason that authorizing bodies demand that you have Professional Indemnity in place.