Yes, my mistake. Landside.
The bit I find strange, though, is that the TRS page on Home Affairs is quite well organised: "You must", "You can't", "You should", "You can". Nowhere that I can see does it say 'You must take the goods with you out of the country'.
I agree it would be an offence to not take the goods as carry-on if directed". There is also "You must ... have oversized and restricted goods sighted by ABF Client services before checking in and take the stamped invoices to the TRS Facility on the day of departure". What is the "TRS Facility"? I wonder if that's only airside.
Interesting that a passenger apparently needs to view the ATO website for that info when it's not on the Home Affairs site.
Where does the ABF website say it checks goods are exported?