“Models show that if 80 percent of people wear masks that are 60 percent effective, easily achievable with cloth, we can get to an effective R0 of less than one. That’s enough to halt the spread of the disease.”
https://www.theatlantic.com/health/archive/2020/04/dont-wear-mask-yourself/610336/
We can do our part to slow the spread of covid-19 by requiring customers to wear masks in order to receive service at Starbucks stores. Starbucks already requires partners to wear masks, but this is only protecting others from employees and is doing nothing to protect employees from customers and does not protect customers from each other.
Starbucks China requires customers to wear masks before entering stores, we can and should do the same here in North America.