From Forbes on 28 June 2020

For retailers, knowing how many shoppers were in their stores at any given moment used to be a matter of profit and loss. Now it's a matter of life and death. Video cameras and traffic-counting systems in place for decades are being re-deployed in the Covid-19 era to monitor compliance with occupancy and social distancing rules and as health screeners.

Retailers are also exploring Covid 19 traffic monitoring solutions being adopted by office buildings and airports, such as mobile apps that conduct health screenings and that let pre-approved visitors open doors or activate elevators with their phones.

article: The New Science Of Counting Shoppers: The Tech Tracking Customers In The Age Of Coronavirus