Kon, in concept it has advantages for people to know who is admin, but, there are greater disadvantages. As to first, a lot of players don't know how to use u@ "to send a message privately to an admin" and secondly, those who are on the cheating spree usually check who is admin, some are lazy and just type /admin, some more sophisticated cheaters join forums to know the current admin list. So it is a bit tat difficult for administrators to be known and catch cheaters. Best is to do it quietly while cheaters do not know if an admin is in the server.
I am not Head Admin of either DD2 and Public, but as a normal administrator in those servers, these are every day problems a lot of admins have faced in the past. I rather have it hidden.