Now, I’m just a smol folksy goblin, but seems to me that it’s just plain logical and sensible to wear a snuggly respirator (KN95 or better) by default whenever you’re going to be around strangers—whether at the grocery store or a sporting/entertainment event or medical facility or mass transit—regardless of location of venue or anticipated occupancy of venue. All this “mask if unwell/in crowded, indoor spaces” is too much math.