The prosecution submitted that a fine of $25,000 to $30,000 was appropriate, saying there were various failings by Genius Learning, and the children were exposed to risks of harm, including being hit by cars.
The defence argued that was not appropriate and the case was on the lower end of comparative cases put forward, and therefore no more than $15,000 should be imposed.
Saggers said fortunately the boys were not hurt, but there was still a risk.
He referred to other childcare cases including an incident on the Gold Coast where two toddlers were found on a busy road after leaving the Okeedokee centre in 2020.
He said Genius had made a serious effort to take the appropriate steps to prevent the incident from happening again, including updating nationwide practices and policies surrounding fire doors.
The court heard Genius, which had a clean record, had conducted a fire drill a few days before the incident, and there were no problems identified with the fire door.
Saggers sentenced Genius Learning to a $15,000 fine and no conviction was recorded.
The centre remained closed following flood damage.
Genius Learning operates 15 centres across Australia and is responsible for more than 1000 children, and almost 300 staff.