The non-impacted CSUs like SFSU define their local service area as “state of California”.
https://www2.calstate.edu/apply/freshman/documents/csulocaladmission-serviceareas.pdf
So by definition they overlap with the local service areas of other CSUs.
CSUEB already included Santa Clara County in its local service area (as well as Alameda, Contra Costa, San Francisco, San Mateo, and Solano).