Many of the people I have seen on the local news station websites whenever the topic comes up who say they are wearing masks indoors, also fully admit to being fully vaccinated.
Where I live, even if you are fully vaccinated, you are required to wear a mask in Winco. The announce every 15 minutes over the store PA that is required to do so for everyone over 3 years old. We have a tremendous amount of immigrants in that store. On the other hand, Costco has no requirement to wear a mask. You are on the honor system if not vaccinated.