I suggested this a long time ago because I'd heard that certain people were reading the teamchat from IRC while in game, and tested it. I played as President and wrote misleading directions in the teamchat several times and watched their red blips follow my directions on the radar. They weren't following the security- I had only a few, and I had PMed them what I was doing already. It's fine and dandy that people aren't allowed to abuse the public teamchat on IRC, but there's no way of keeping track of it and one person could easily keep it on a separate monitor while playing.
Jonne's reply to my suggestion was that it is cool to be able to see what everyone is doing on IRC by seeing all the teamchats at once. I think this should still be possible, but it should be something that players are given if they can't abuse it and are trusted, not something that they are given by default. I don't know how best to do this, but I do see it as a possibly more significant problem than people realize. I don't often have a plan to post to the teamchat because I only really plan things on the teamchat if I have security that I know have specific skills I could use, but I can definitely think of times where I can be unfairly screwed by people reading the teamchat.
To all you people giving it a simple "-1", you're not gaining anyone's trust here. What's your good reason for wanting to keep it the way it is? It seems that if you weren't abusing it, you'd at least recognize it as a problem.