Wrong Question.
But there was a comment from ex DFATer not to worry about it.
Previous quarantine offenses, and being a smart-cough or troublesome will not be in your interests. Being helpful, and having ALL food/customs items in one open bag ready to go - seems to be a big plus.
The right question is how do they 'score' you - as mostly everyone is pre-cleared before you arrive - or flagged for special attention. They do this by (primitive) data matching, or random chance or police tip-off. They do not want to waste money on false positives - so for legit people nothing to worry about.
What goes into this data matching engine. Well the Privacy commissioner has about 0.02 per Australian to print mundane details, but the loopholes exist.
The possibility of someone detained - leaving because of
a) parking fines
b) tax matters
c) Child care payments
d) flunky arrest warrant ... is a concern.
If traveling to United States, there was something printed in Europe that the sent bank account and credit card details and biometric data - which made the Euro's outraged that the outsourced company did something stupid.
Which boils down to if you have a big disposable income, respectable job or clutch of kids, everyone wants to be your friend. Green opens doors.
If you set off the drug sniff test, look like a smelly tramp, beard, grey shoes, low on cash, and from the golden triangle or .nl - expect to be hassled.
Those who requiore clearance or vetting - well they ask for photocopies of your passport and more. No privacy - unless you are an absent minded person who scores lots of business 'freebies' - until time catches up.