There are many more than those campuses which have BSN programs among state universities in California.
However, most BSN programs at California public universities have pre-nursing → secondary admission to nursing, rather than direct frosh admission.
Declining admission does not result in a 1-for-1 admission of someone else. Colleges / majors know that each admit has some (probably individualized) chance of yielding, so they admit more than the target size of the class. However, if enough admits decline so that the college / major underyields, then waitlisted applicants can be admitted (some colleges start admitting from the waitlist even before May 1, if early declines result in a projected underyield).