I suggest "temporarily" disable "Talks" function for those who are competing in official competition.
In today's CF #272 competition, I got contest1234's message which want to get a copy my code.
I thought it's a little annoying and this is cheating, so I didn't reply.
Of course, when contest is ended, then this function should be available again :)
My statements seems a little misleading.
I think competitors "in contest" should not be allowed to send/receive any message (excepts "Questions about problems" function in their contest or send to/receive from those who manage the contest).