I can see an argument for forcing public companies to post anonymized data about salaries, perhaps including gender, race and age. Thus ensuring employees or advocates can understand if they are being treated fairly. But, My salary is very private. Exposing it means I have less leverage in some negotiations. Not just wage, but sticking with that example, what if employers created a cabal that said "hey, we're not going to give anyone more than a 10% raise for jumping ship to ensure that theres still some incentive, but less, for 'disloyalty.'" This isn't exactly speculation either, there have been numerous reports of companies creating back door policies not to hire away from each other, which ultimately only hurts the employee.