California Employers Must Provide Salary Ranges When Asked

I've been watching this for a while. I think it's great but afraid it might be another piece of barely enforceable employment law.

Is "0 to ∞" a valid answer to salary range? If not, how narrow does the range have to be?

Thought I'd repost this - given it took effect on January 1st. Employers can also no longer ask for, or try to obtain, salary history as well.