Considering that they already publish how many legacy students each university takes each year, this law doesn't really do anything new other that stronger wording.
It's a good start. It's paving the road for penalties at a later day.
I guarantee you penalties will be added within the next 20-30 years because of the political aspect in California.
Us Asians and Latinos are the plurality now and underrepresented in legacy admissions - and it's a single voter issue that could flip entire demographics to vote for a candidate.