"Leave Me Alone" option

[Beorn]

If I understand correctly, the Leave Me Alone option is supposed to prevent rivals from settling within 6 tiles of the human player's city.

I have been seeing them settle as close as 4 tiles away, with the option chosen. Maybe there are exceptions for war or for the city only being an outpost, and these account for what I am seeing. Or maybe the option isn't working as intended.