That sucks, I use that method to read messages through party/clan/trade/hero chat while macroing.
I think the issue here is people spamming trade shouts using macro, then they get /blocked by too many people.
This issue occurs when you receive chatban that way (the old anti-RMT you released years ago), when you type out a message it looks like it goes out in "All" chat (but in reality nothing is sent, and noone can message you).