That is exactly what I do too. One Sunday tho I was in a very local shop where I only get bits n bobs, emergancy food, and a newbie staff member did the exact same thing to me, followed me down the aisle and offered me a mask. I emailed the owners to ask if this was a new policy and got no answer. I didn't go in for 3 weeks then tried again and no sign of him and no-one challenged me again. I think he was just a jobsworth and yeh fkn hate jobsworths!!!!