It weirded me out when I moved here, but in practice, it's enforced like anywhere else: at the beginning and end of school days.

Since a large fraction of kids are driven to school (at least in southern California), you know that this is happening because of the massive traffic jam near the school.

Illinois has these "no turn on red when pedestrians present" signs and I have no clue how thats supposed to help anyone because pedestrians usually get hit because they aren't seen by the car.

The idea is that you would be going slow enough already (and if not, slow down). Then, if there’s no children, you can speed up.