Even though almost no one is traveling right now due to the novel corona virus, it is still worthwhile to know about a recent decision of the Federal Circuit Court that relates to false answers on an outgoing passenger card: Dalla v Minister for Home Affairs & Anor (2020) FCCA 454 (3 March 2020).
We have seen from previous cases that giving an incorrect answer on an incoming passenger card - for example, failure to disclose a history of criminal convictions - can lead to visa cancellation.
The decision in Dalla takes this a step further: in this case, it was held that giving a false answer on an outgoing card, in this case, concerning the amount of Australian currency that was being taken out of the country - will also be considered a contravention of section 102 of the Migration Act (which requires that the information provided on a passenger card be accurate) and will therefore support cancellation under section 109.
It would certainly be worthwhile to bring this to the attention of your clients - for example, if you're assisting with the preparation of an application for a Bridging Visa B, that would be a prime opportunity.
I would venture that most visa holders will have no idea that providing incorrect replies to the questions on the passenger card can get them into very big trouble.
Forewarned is forearmed.
For details, take a look at the detailed analysis of the case that is on The Migration Messenger (subscription required).