That's kind of your call. I have never done so. We spun off from a site that was run by a major religious denomination so the ministers of that denomination who came over often mostly use variations of "Rev(real name)" or something like firstname plus last initial (though one does not). Given that religion and faith are supposed to be our focus, having them "in the open" is kind of nice since they are technically subject matter experts. So I am cool with that. That's their call. Now, if you think that the subject matter might turn using real names into a risk for someone, then it might not hurt to make it a "guideline" or recommendation. In the end, I am not sure how you would enforce it as a rule.