(a) That's right. Section 18 of the Australian Consumer Law says that a person shall not, in trade or commerce, engage in conduct that is misleading or deceptive, or that is likely to mislead or deceive.
The arguments made by Tyler raise three separate questions:
Can a statement that is factually correct be misleading?
Would Tyler's advertisement be the cause of anyone deciding that Georgie Ripper would be in the show?
Does it matter that misleading conduct takes place unintentionally?
As regards the first question, it is possible for a statement to be misleading even if it is factually correct, depending on the context in which it is made, the manner in which it is presented, the persons to whom it is made, and so on. Advertisements that are presented to a wide range of persons, using large and small text that emphasises only certain points, may well be misleading, particularly considering that advertisements are often only glanced at, or viewed at a distance.
As regards the second question, it is important that any likely misapprehension of fact is causally linked to Tyler's conduct rather than to some other factor. See McWilliams Wines Pty Ltd v McDonald's System of Australia Pty Ltd. In the present case, the form of the advertisement, and the use of large and small print, are likely cause people to wrongly believe that Georgie Ripper will be in the show.
As regards the third question, s 18 imposes an absolute prohibition on misleading conduct, regardless of intention. It does not matter, therefore, whether Tyler acted with the intention of misleading anyone or not.