They are trying to pass this in Philadelphia in May. Comcast and the local Chamber of Commerce are suing to stop it citing that it's a Freedom of Speech violation. Besides being able to freely low ball candidates who started behind the 8 ball (women/minorities/people who didn't go to elite schools), is there a real argument for companies HAVING to know your previous salary?
1. I made X at my last job where X is far less than what you are paying your current employees. Well as a business owner and negotiator if I offer them X + a small bump I can probably get away with paying less.
2. I made X at my last job where X is far more than you are paying your current employees. You either are going to stretch the budget, or negotiate.
So it is always a negotiation unless the person says they made less. A true negotiation is "How much are you asking for?" A person selling products isn't going to tell someone what they are selling their products for to a competitor. They are both going to negotiate a price or decide not to do business.