While I agree that being this age doesn’t automatically warrant having a smartphone, any kid who has an allowance can buy a bargain-basement Android phone to use over wifi. And smartphones are very concealable.

(IMHO, once a kid has figured out how to do this, they have earned the privilege. It’s part of growing up.)

A responsible and forward-thinking parent could provide a Graphene OS smartphone if the kid absolutely insists on having one, to limit the privacy damage.