This is not addressed to anyone in patricular, but unlike in the UK, folk can drive around NSW with nothing other than their Green Slip.
"If you cause an accident, your green slip insurance covers medical costs for:
other road users, such as drivers, passengers, pedestrians, cyclists, motor cyclists and pillion passengers
injuries caused through the use of a trailer.
Your green slip insurance does not cover:
you for your personal injuries if you cause the accident
damage to property or other vehicles."
Note that the Green Slip will not cover damage to anyones vehicle. So if someone drives into the back of your car assume they have no insurance and that you (or your insurance company) will have to take them to court to recover costs. You need to get some basic info:
Or think of it like this. Some random person starts chucking stones at your house windows, smashing them. You probably wouldn't accept their word that they would pay for the damage. You would get their details (or call the cops).