I think the attitude to mask wearing seems to be different in different countries/cultures. In South Korea, where DS has lived for several years it's long been considered polite to wear a mask if you have even a sniffle, to minimise the chance of passing it on to others, so for them it's no longer an issue. Also, over there they're used to doing what they're told by those in authority, a totally different culture to the one in the U.S. (and, to an extent, here in the U.K.). It might bear pointing out, that over in East and South-East Asia, they have kept their infection and death rates very low (so far, fewer than 500 deaths in SoKo) - could it be due in part to these attitudes? Probably best not to mention China though, given that the virus originated there!