Hello there, I'm just wondering why this didn't happen yet already?
It happens all the time, I guess you are not aware of it or haven't spotted someone doing that.
How it happens and who does it?
- Well only few admins (lets say 30% of all admins) go in server with different nick get good evidence and check players and afterwards start playing with their nick, however the rest go in server and the first thing you see in White chat is : HIIIIIII IM HERE ( -.- ).
So in conclusion, this suggestion is already implemented by the admins, but the thing is that not all admins do that. You could have wrote this as a Tutorial How to get hackers, rather than suggesting it. 
Cheers,
Popay
Further opinions?
Oh, noes you didn't understand it... I am 100% aware when there is an undercover admin. It's usually no one in the server but Ultor and I rarely do it (in Jailbreak)
Let me explain it in an example: When you kick a player, me for example it says Popay | JLz has kicked CrimeMiz from the server.
But when amx_show_activity is set to 3 it will appear to the normal players like this "Admin has kicked CrimeMiz from the server." and will be viewed as "Popay | JLz has kicked CrimeMiz from the server." for the other admins online...
Or in the tsay the big chat when you speak your name appears before the thing you sent. is there an actual need for your name to appear there? I think not because it's usually a warning or an information.
That'll keep the admin Anonymous for new players without them knowing who he is which will make any dead player scare the hacker and make him think he's the admin and he might be spectating. So at that time when new players don't know who admins are they should respect each player because they have no clue who is the admin.
If admins cooperate well as they are supposed to there will be no confusion... Just communicate to each other a little bit more o the admin chat. For example: each admin online at the same time can chose a colour to use in the big chat if he is willing to expose himself as an admin in front of the players, and so on for different commands.
This will be really helpful because as I said it's usually new players that break the rules and use cheats.