[yodsanklai]

> It is now common in Taiwan subways and trains--basically everyone wears a mask.

Not clear if it's useful to wear a mask if not displaying any symptoms. I didn't see any official recommendations for doing so. I've been traveling quite a bit in Asia these last few weeks, and I'd say 80% in planes wear masks. However, most of them don't use them properly. They take them on and off, reuse them, adjust them, touch their faces. Sometimes they don't even wear masks, but piece of clothes.