In practice, most schools lack anyone with enough technical literacy to lock down the device. So they just hand out unlocked cheap android tablets with all the stock spyware and advertisement pre-installed.
They have some things used in lessons, but they're all given out at the beginning of the lesson, then gathered at the end.
You could argue that it's a problem they they assume home access to such things anyway - especially in later years - as things like online 'homework' is the norm.
And googling only seems to find examples of the low income programmes. I struggle to find a single instance when devices are handed out to kids and not keep at school and only used in specific tasks - like the old trolley of laptops was a few years ago.
Or breathless reactionary commentary without any actual examples of course.