I found it unclear because the title of the article and the title of the TV show imply it's only during school, but it's only the second paragraph that it mentions "completely". It seems to contradict the opening sentences.
Never trust headlines, they are optimised for clicks, not accuracy. It's also common for headlines to be written by someone other than the article body, someone who potentially only skimmed the article, and changed based on A/B testing.
And TV show titles.... basically useless.
It's only because most UK secondary schools already ban phone use in school time that (in context) it obviously means round-the-clock.