During our last 2 clan wars we have received no less than 6 messages from different clan members of the clans we were in direct competition with. 1 wanting us to stop playing for Microsoft points, 2 have asked to join us and the rest were just abusive. I can see why there is no direct link to the other clans but I think someone has mentioned a way around it.
What these people didn't realise is that by sending us a message they instantly gave us access to their friends list (full of clan members) so we knew what they were playing and could dictate our strategy around this and beat them to whatever node they were going for. this helped us win by such large margins 690-215 and 858-265