While I agree in principle that it is "your responsibility to investigate the instructor and verify his credentials," I would suggest that the body issuing credentials has some responsibility as well. If there is none, what's the value of certification?
I happen to teach a unrelated state licensing course that does not require me to pay $300 to some "issuing authority" to be certified... but I did have to submit my syllabus, tests, etc. to the regulatory commission and a member of that commission attended and audited my second class.
Obviously, that's not a guarantee of competence either but it's evidence that the commission is trying.
I'm not upset over wasting my money... but for gun owners this is yet another example of "we have met the enemy and he is us." In most ways I would say that I'm fortunate to live in a state that hasn't restricted gun owner's rights... but we need to do a better job of protecting those rights by acting responsibly. If we don't police ourselves, others will be happy to do it for us.
It appears to me that NRA Instructor Certification is a simple matter of money. You have the money, you can get certified. I was shocked at how little information is available on the NRA site regarding certification, instructors, etc. What's there reads like "take this $300 course and be a certified instructor."
As John points out, in NC they don't consider NRA Certification a qualification to teach the CC Class. That's a shame and the NRA OUGHT to be embarassed. Same with the Ohio story... maybe the NRA should have some sort of rating system like Ebay and most of the auction forums where students rate their experience with the instructor... or do we care more about the competence and quality of the people we buy guns from than we do about those who teach people how to use them?
You know... that might not be such a bad idea!
Perhaps some of the certified instructors who take teaching seriously could lobby the NRA... or start an effective professional association of instructors!