And just because you have a certificate doesn't mean you have a clue how to do something. I did a PAT course and actually know nothing about it because the college were so focused on passes that all we did in reality was go through old exam papers so we knew a million questions off by heart. When we sat the exam we knew all the answers. Fortunately for me its not something I use or need to know about in my work. But I could go out with my certificate and pass allsorts of dodgey stuff if I wanted.