It's certainly important to make sure your employees understand the real message. At a previous company, lots of folks were fired or "resigned" and a lot of us in the engineering side would comment on it from time to time, and of course worry a little. One day we had a frank conversation with our boss about it, and the thing we didn't quit grok when seeing these firings were that it was sales/marketing - where you can't as easily check out someone's GitHub or have them solve some programming assignments.