Right. Even within the UK, there are observable differences in the day between southern and northern points. If, say, someone from Kent was to fabricate a story

Right. Even within the UK, there are observable differences in the day between southern and northern points. If, say, someone from Kent was to fabricate a story in Glasgow set around twilight, you'd immediately notice their timescales are off. You could technically remember that without knowing why, but for real people organising facts like that under "things that are true because the earth goes round the sun, is tilted, and is round" is easier. A skilled worker organises their knowledge.