I had an idea while reading through the "Do noob builders BOTHER you?" topic down in S&T. This idea could be implemented alongside default-installation GUIDs.
The idea: Implement a server-controlled setting allowing only trained players to enter, or allow any players to enter (depending on variable value in server QVM) as well as implement a complete, single-player training
Why do this?: This would severely reduce the amount of "Download-Install-Decon" Unnameds in various servers, plus it would eliminate totally clueless builders/new players.
How to do this:
1) All Tremulous installations would contain a GUID with a certain string (such as "NOOB", to be evil) in them.
2) All Tremulous server QVMs would contain a variable allowing only those with non-NOOBed GUIDs to connect to them or not.
3) Upon connection, the server would query the client for the specific string in the client's GUID, like "NOOB" (evil example

) and if that string exists, the connection would be denied as in Step 4 below.
4) Those with NOOBed GUID, upon joining a full-GUID server, would be notified of a message like "Connection denied: This server only allows players who have completed the Tremulous Training Course to connect. Please proceed to the Main Menu and click on 'Tremulous Training' to learn the basics of Tremulous and be able to connect to full-GUID servers."
5) Players with non-NOOBed GUIDs would proceed through the connection phase without any change to the current formula.
Onto how the actual training would work:
A special map would be made specifically for training (which I'd be happy to do if the project got greenlighted). A human and alien base would be set up in this map, and current bot codes would be implemented along with a few area triggers to activate them.
The player enters the game as a spectator. The console then begins to talk the player through various things via chatmode/consoles, walking them through the team selection menu, the spawning class menu, chatmodes, using weapons, the names of various structures, basics of targetting/movement, and finally the basics of base building (no advanced techniques; just the importance of structures and how to build them).
There would be 3 separate training sessions; basic information (chatting, terminology, binding, naming, etc. that isn't team-specific), human technical (covering all human weapons, base building, and general tactics), and alien technical (covering all alien classes, base building, and general tactics.)
As you can see, this would take a generous amount of coding. However, it would SEVERELY diminish Unnamed deconners (since most just download the game, install it, and then raise hell for a few hours until they get banned from every server and/or uninstall Tremulous) and would increase the level of basic intelligence among new players wanting to learn the game.
For an example of the training-required formula, look to America's Army, which really eliminates noob players on game servers.
One source of inspiration is as E-Mxp mentioned below; using the FreeSpace 2 training format would be good for this.