I agree that this is very bad on google's part of course, however I don't think the schools should just lie down and take it. As others have said, installing their own OS should be the way to go. It doesn't need to be 1 person manually installing the OS on each laptop, there are Infrastructure automation tool like Ansible that can, once set up, manage installation and configuration of an arbitrary number of devices. All the device needs to do is launch a web browser from what I understand, and pretty much every linux distro should be able to do that. If they choose one with a friendly DE, then it makes it easier to use for the kids. The devices will most likely run much better on an OS without bloatware too.