As coronavirus cases surge, California is the latest state to require face masks

[Ms. Toad]

13. In the most dangerous locations, there are other ways to enforce it

The local public health departments are generally the investigative and enforcement entities for public health orders.

If the police won't enforce individual mask slackers, report the business (a closed space, which is inherently more dangerous) to the public health department. They will investigate and (if necessary) fine businesses that are not in compliance. I'm far less concerned about the lack of mask wearing in open air spaces - and most enclosed spaces fall under health department jurisdicitons.