walnut creek is a well to do, mostly white suburban community, 16 miles away from oakland on state freeway 24.
to get to walnut creek, the “shoppers” would have to cross the bay bridge in both directions. the bay bridge has many video cameras to monitor traffic conditions.
most likely imho the “shoppers” came from oakland, not san francisco.
No, no. Walnut Creek is on the east side, the same side of the Bay as Oakland, an easy drive up the expressways or tunnel from Oakland, Berkeley, or their slums (Richmond, etc.) No cross bridge commute needed: You’re thinking San Francisco.