I've not had the chance to try it, but I like the idea of turning it around: "Sure, but first _you_ give _me_ a detailed histogram of salaries for your employe

I've not had the chance to try it, but I like the idea of turning it around: "Sure, but first _you_ give _me_ a detailed histogram of salaries for your employees [in similar positions/rank]" I suspect you won't get that histogram, and they'll be offended you asked. Maybe they'll understand why you don't want to share your salary.