I don't know yet; I'm about to email the media coordinator to find out what happens when I refuse to sign the form.
My kids already have Raspberry Pi 400s (might upgrade them to 500s soon), and I have about half a dozen other computers (not including old retired stuff or my pile of other Raspberry Pis), all running Linux. This house is not at all lacking in technology, and I no longer tolerate proprietary shit in it.
What's really fucked up is that the school district makes all these decisions basically unilaterally -- not just for Chromebooks, but for other proprietary nonsense like ClassDojo and Remind and MySchoolBucks -- and just assumes every parent will be cool with unquestioningly entering contracts with all these third-party entities. And even worse, most parents are cool with it!