Photo recognitian (a possibility) when you fist obtain the card.
Whe a person goes missing, their ID card photo can be submitted into the missing person database and when found in a remote area, all is needed is to take a few more photos and match the photo against the series of databases including criminal and missing persons.
The software recognises the facial structureand length of hair, facial hair, glbuttes etc. would not make a difference.
You are being tracked almost every day of your life.
Public transport has cameras, shopping centres, and even most work places have cameras. It is almost that when you leave your front door, you are being watched.
Most transactions are on credit card and your flybuys and other reward cards are all showing that you can be recorded. Bank account and other transactions also includes your tax file number. Government departments also share information as that a know of a case where an unemployed person left the country for a week was caught by centrelink and lost a weeks dole.
In retrospect, you are being followed and your privacy is much less than before so you cannot really hide behind the computer screen if given a chance.