The precedent exists unbroken to this day and requires the arresting officer to testify about the presence of children during a hearing. This is why signs throughout Illinois in school zones have smaller lettering saying "When children are present." In other words, the school zone speed only exists when children are present and otherwise it is the default speed for that road (prior posted speed limit).
The Mayor's legal research however failed to acknowledge those pesky letters below the 25 mph limit and now they are putting the onus for detecting children in these photos on the companies bidding to install the latest network of cameras. Ostensibly to generate more revenue, the Mayor hailed the cameras as an important tool to protect pedestrians, especially children, from reckless drivers.
When these cameras are eventually installed, drivers will be scrutinizing the photos for the presence of children. Drivers should contact an attorney if they feel that their ticket can be challenged. The City's attorneys will have trouble convincing administrative law judges that the ticket should be enforced if there isn't a clear image of a child. The City has the burden to prove the presence of a child and adult pedestrians do not trigger the lower school speed limit. It will be a mighty burden to meet and a canny defense attorney can really make their task frustrating, if not impossible. However, cited drivers cannot challenge the ticket if they were exceeding the prior posted speed limit.