If people can set it for their journals individually, would my site preference still override it? It would be really confusing if I couldn't tell whether someone picked month or day first if the year is last. With the year first otoh I have never seen the day to come after the year (i.e. yyyy-dd-mm is not something I've encountered, with the year first it always is year-month-day). So that is why I like the year first display. It's unambiguous.

If there is choice maybe the separators could be used to indicate which format was chosen? From what I gather the US with the odd month first quirk more often use mm/dd/yyyy with a slash while with day first it's more dd.mm.yyyy with a full stop as separator.