Yes, because I work on government grants. Part of the grant application process is that you specify who is working, how much time they will contribute, and what the salary is.
There are two possible stable cases:
1) No one knows what anyone makes. People feel comfortable with this situation - everyone has their own privacy. But, you never know if you are screwing the system or if the system is screwing you. The person next to you who does the same job with the same experience might earn twice what you earn. That would suck yet you wouldn't even know to demand a raise. You don't know if working hard will help you get ahead or not.
2) Everyone knows what everyone makes. When you enter the position you have full knowledge of what your earnings will be and what they will likely become. You know whether a raise is something that you should fight for or not. Etc. It is a pleasant situation since salaries tend to be similar with only minor differences due to work quality and experience. Slack off, and you'll soon know that you make less than others, work hard and you might get a raise a bit above the others. It is good motivation to work.
There is one horrible case:
3) Most salaries are unknown but someone finds out. All hell breaks loose. Jealousy arises, people get mad or quit, or stop working as hard. Those who were screwed take it out on the company, those who were overpaid are hated. I've seen a business almost crash when this happened. Half of the employees quit or demanded serious raises that couldn't be afforded. Thus stable case #1 can blow up if the information is let loose.