The ACBL clearly does not have a good way of getting the word out to the 'hoi-polloi', including club-level directors, or at least not a good track record on doing so.
I agree, in principle, with the premise that one should rule according to what the law
says rather than according to some rumored interpretation that "everybody knows" but nobody can put a finger on an official statement to that effect. However, in practice, if a club level TD rules that a "could be short" opening is not natural (which is in fact what the regulation says*) so that any defense is allowed, and the pair(s) who receive that ruling then go to a tournament where the TD "knows" that the regulation doesn't mean what it says, but that "could be short" openings are to be taken as natural, in spite of what the regulation says, then those players are going to be
very unhappy when the ruling does not match their expectation.
*One could argue that this is in fact not the case. The regulation states that openings in a minor on 3 or more cards are considered natural. It doesn't say
anything about openings in a minor on fewer cards. So an opening on fewer than three cards might or might not be natural. Of course, this kind of ambiguity is deplorable in a regulation, but that doesn't mean it isn't the position of the RA (ACBL) that this is the case.