I feel that should be covered by regional locales set on the browser or system, like EN_US, EN_GB, EN_CA or ES_ES, ES_MX, ES_US. As a user also pointed out, if

I feel that should be covered by regional locales set on the browser or system, like EN_US, EN_GB, EN_CA or ES_ES, ES_MX, ES_US. As a user also pointed out, if I'm British and am travelling to the US, changing the date order of an app/website just because I moved is even worse, it can be very confusing.