Flawed as may be, that’s reality though, and it’s meant to put into perspective to those claiming check out dives are easily done and no one should object to it.
Which btw, in the incident example you provided, I read it and saw absolutely nothing in there a check out dive would have solved the issue, did you? From what I can see, the couple would have passed this “30 seconds easily done” check out dive and deemed fit to dive, in fact, that dive was at the end of dive day, so, seems like some previous dives were conducted without issues. The couple made a judgmental error.
These “easily done” dive checks some are claiming are designed to check divers competence regarding basic dive skills.
In addition, the number of divers also have nothing to do with it, that couple, for all we know, would have done the same mistake if there were only a half dozen divers on that skiff.