Do you have an example of this fraud? As many years as I've been diving, many of those in the industry and even teaching, still I've yet to see any fraud. Oh, I disagree with many of the procedures and standards kept by the industry, but that's not fraud.
Yes, it actually is. Remember the Ford Pinto? Takata air bags? The auto industry is often guilty of selling bad products until they are caught and sued.
Unfortunately, people often make buying decisions based on impulse, not research. Caveat emptor, sure, but few actually heed that warning. Even then, there's scant information about bad instructors, because students often blame themselves.