"Do you have any criminal conviction or finding of guilt, which is less than ten years old, or any juvenile criminal conviction or finding of guilt, which is less than five years old?"
So a DUI would almost certainly be dealt with by conviction and fine or heavier penalty and would have to be declared.
A small shop theft as a first offence would likely be dealt with either by diversion (no finding of guilt therefore not declarable) or good behaviour bond without conviction (finding of guilt and therefore declarable).
For ten years I admitted to a civil offence, which was using a radar detector on a motorcycle.
Road traffic matters are dealt with under the criminal law...you almost certainly entered a plea of guilty and pleas guilty are not part of the civil law. You correctly admitted a conviction which was of no consequence to your status as a fit and proper person.
But if you didn't admit it and CASA took issue with the failure, you could be charged with perjury which would be of great consequence.
Kaz