Market Gap and drop, what have we missed?, page-129

Agree with your sentiment. The ASX listing rule 3.1 covers it as follows:

"3.1 Once an entity is or becomes aware of any information concerning it that a reasonable person would expect to have a material effect on the price or value of the entity’s securities, the entity must immediately tell ASX that information.
3.1A Listing rule 3.1 does not apply to particular information while each of the following requirements is satisfied in relation to the information:
3.1A.1 One or more of the following 5 situations applies:  It would be a breach of a law to disclose the information;  The information concerns an incomplete proposal or negotiation;  The information comprises matters of supposition or is insufficiently definite to warrant disclosure;  The information is generated for the internal management purposes of the entity; or  The information is a trade secret; and
3.1A.2 The information is confidential and ASX has not formed the view that the information has ceased to be confidential; and
3.1A.3 A reasonable person would not expect the information to be disclosed.
3.1B If ASX considers that there is or is likely to be a false market in an entity’s securities and asks the entity to give it information to correct or prevent a false market, the entity must immediately give ASX that information.
ASX Listing Rules; Guidance Note 8."