Nowhere in the manual you will find a statement to turn off your common sense... Somehow people still do.
Passing for your drivers test doesn't qualify you for driving formula 1 cars, and that does make sense while cavediving with only OW training does not ? I just don't get it.
The phrase additional training for anything that is not covered in OW IS mentioned often enough, every chapter at least tries selling more courses, that should ring a bell. Also it is stressed that you are trained to dive similar or better conditions than during the course.
They could have known and should have known... That is what you are given common sense for ... To use it.
BOLD and RED added. This may be part of the problem. When people sign up for a course they may be turned off by too many attempts to sell them more courses. It may be they think the advice is more money driven than need driven.
If we stuck to the letter of this.. we would never improve as divers. I just can't buy this! I have become a better diver by diving progressively more and more difficult dives as my skill and confidence improved.Also it is stressed that you are trained to dive similar or better conditions than during the course.