Californians in counties where the coronavirus is raging the most must change their behavior starting Saturday. Between 10 p.m. and 5 a.m. anyway. Erin Allday and Heather Knight discuss Gov. Gavin Newsom's order for purple-tier counties, which follows similar efforts in New York City, Los Angeles and Europe, though scientists are dubious about its efficacy. | Unlimited Chronicle access: sfchronicle.com/pod
