It's relevant in the same sense that they feel the risk is sufficiently low for their particular circumstances that the threat to their well being is not enough to mandate it.

Great point.

Some places, like Denmark, have Cadillac-grade health care systems and are able to manage infectious disease on a national level like a Formula 1 team. They are able to be less stringent because it's far easier to get a handle on disease outbreaks.

Other places, like the US, are running 1992 Chevrolet Cavalier-grade health care system and are able to manage infectious disease on a national level like a group of drunk fraternity members. There's little choice but to use every blanket policy available to try to keep disease in check.