there are always unintended consequences to this...using geographical quotas is not the same thing as using race. However, other majority and minority groups may see this as an easy ‘in’ to a school. Just move into a low-scoring predominately minority district to gain easy entrance to an otherwise unattainable school.
There may be a much higher demand for slum homes ... buy one just before sending in your child's application to UC Berkeley, get in based on "diversity", and sell it to someone with a kid graduating the next year. It could boost housing values in the worst slums of California, while making the racists in the UC system feel good about themselves. It's still stupid, but at least it's fun stupidity.