In certain Nordic countries (Sweden at least, I believe), all tax data is public. By extension, everybody's income is public as well. It doesn't seem to be an issue.
https://news.ycombinator.com/item?id=9907147
Looking further, it appears that Sweden has decreased the amount of transparency by requiring that people make specific requests that notify the taxpayer of the request.
http://www.businessinsider.com/sweden-salaries-freely-availa...
Apparently, there were issues. I'd like to see this experiment run for a longer period of time in more culturally diverse environments, though.