I was only referring to the interview/recruiting process - not for existing employees.
The big problem with exposing individual salaries is that most people overestimate their own worth (except, interestingly, some of the most productive people). It's similar to the phenomena that well over 1/2 the drivers think they are better drivers than the median skill driver -- which of course is impossible.
I suppose open salaries could help in one way if managers are bad at giving feedback and taking action. Those employees who think they are better than another employee who, in fact, is much more productive than they are may eventually quit just because they are angry that they are not making as much money as the other employee. However, I've never had a big problem with housecleaning though so likely I got rid of them already in a convenient layoff or other personnel action.
Of course in an environment with little salary diversity based on merit, there's less reason not to disclose salaries.
I do believe in exposing salary grades (low, mid, high for example) but not individual salaries and title:grade relationships if those formally exist.