Have a friend that has it, over 30 days with ‘low grade fever’. He believes he got it standing in line at a Home Depot for an hour. Which brings me to my point - I believe ‘exposure rate’ is more important than wearing a mask. If you need to spend more than 5 minutes in a store, finish your shopping and come back later - works for me.
I believe you are on the right track. most of the troublesome cases are “in a waiting room fir 1 hour with a Covid person”.
I’m sure this is why they are not allowing people in bus and restaurants ...Barbers and hair stylists .... etc.
I just order on line and get the curbside pickup at Lowes and Home depot , no need to stand in line with someone coughing or sneezing.