I tested this little theory of putting mods in a fourdeltaone server folder while connecting using alter-rev client. This is what happens: Joining a Mix mod
Joining Zombies:
Joining a fourdeltaone server with no mod gets this:
So it does work, as soon as you join the server it boots you out, but not all people want mods on their server but again if your really having a problem with it then do what dango said and add an anti-noob mod or just something simple like no grenade launcher. Simple.