Here's what I do in order to find out if someone with the tag is an admin.

When they log in (fully to show on sb_status) type ma_admins. If they don't show up tell them that they have 30 seconds to prove their an admin or get banned for a week. If they don't talk or respond ban them for impersonating an admin. (not really a week, that's just to get their attention.)

Make sure they're logged in, though. If it just said "<insert name here> <ibis.a> has connected" and they haven't shown up on the list yet, it's because they aren't fully logged into the server. Once it does the "No bans found for <insert name here> <ibis.a>, yada yada yada" that's when the hammers should start falling if they don't show up on the admin list and are just wearing the tag to impersonate an admin. If they are a noob that just hasn't had their admin activated yet they'll tell you in a flash. Likewise, if they are a noob that just hasn't had their admin activated yet, they can ask Zero to un-ban them when he can get around to it.