I could actually see this working, under three specific conditions:
1. This hour is the last hour before closing. And immediately after, the store is thoroughly sanatized.
2. This can only happen at places with slef-checkout. All other lanes are closed.
3. During this special shopping time, employees are not obligated to help, talk to or be near customers. You want to be mask free? You gotta commit to he self-serving in every sense of the word.