Before patch 1.03 it used to be possible to send a chat message with no recipient by doing:
/p And then i type my message here
In other words, it was possible to send a message to your party, even when there was no one else in your party. As of 1.03 this is no longer possible. It yields the error message:
You can't do that command when not in-game. Type /? for more info.
Is it in any other way possible to send a chat message to no recipient? It sucks to have to spam friends or public chats with bogus messages...