When you say diners weren't wearing masks in restaurants, do you mean they weren't wearing them at their tables? Nowhere that I know of requires that, and it's pretty impossible to eat and drink while wearing a mask. As most restaurants on the island are outdoors , I also don't think it's necessary to wear a mask when entering and being seated. At indoor restaurants, sure. We did notice a lot of "chin masks" on staff at various places, but they pulled them up when they got near patrons.