What problem is the CA legislature trying to fix, and how will they be able to determine if this legislation fixes it?
Interestingly, I work for a movie company, where all work is contracted. For directors, screenwriters, stars, etc. It is very traditional to base pay on your "quote" = what you got paid last time. Now they can't ask what the person got paid last time.
Not that it should be any of a company’s business, but if they want that info they can get it. That said many cos. use salary services to inform compensation.
Aggregate salary data, not specific to the individual, remains allowed.