I saw only one un-masked human in my store today (well, I saw two, but the first one, a guy, rushed over to lane 7 to get a free mask). There's something about attractive women in their 30s that seems to configure into "anti-masking". Maybe they think no-one will love them sufficiently if they can't see ALL of their pretty face...
She didn't come through my cash, fortunately. I had one yesterday, and in an important, to me, coincidence, I was helping the previous customer pack, and didn't notice her standing there, unmasked. It's my personal policy that if I've made them wait, I feel obligated to serve them. If I'd seen her approach, I would have asked her to use another till. As it was, I found myself being uncharacteristically rude-ish to her. (Not really rude, and I didn't say anything, but I kept backed well away from her and sort of pitched her groceries right to the end of the belt.)