Create a scheme to legally recognise those exempt from wearing face masks

This will allow those such as retail workers to challenge non mask wearing customers who aren't displaying an exemption. This will stop the people who believe that covid-19 is a conspiracy, being defiant, above the law etc. from disrespecting other customers and workers who are willing to wear masks to protect themselves and others. Personally I have had several customers feedback saying that when other customers who aren't displaying exemption and aren't wearing a mask it makes them feel exposed and vulnerable.