Considering the echo chamber in which I was at school, my friends would have simply used some Raspberry Pi (or a similar device) to circumvent any restriction the parents imposed on the "normal" devices.
Oh yes: in my generation pupils
- were very knowledgeable in technology (much more than their parents and teachers) - at least the nerds who were actually interested in computers (if they hadn't been knowledgeable, they wouldn't have been capable of running DOS games),
- had a lot of time (no internet means lots of time and being very bored),
- were willing to invest this time into finding ways to circumvent technological restrictions imposed upon them (e.g. in the school network).
Hypothetically, if every kid in your social circle had their device "locked", the adults would probably have a very hard time the kids away from their devices, or just relent, because the kids would be very unhappy. Although maybe with today's knowledge, most people will naturally restrict new kids who've never had unrestricted access, causing a slow culture shift.