Even though it's not the exact same thing, we've suggested a Server speech/announcement speech so we are able to broadcast messages to all the maps within the game when we would need to restart the server, posted news or other happenings in the community.
If kov makes this it would be something similar to your idea.
In general though it's not a bad idea or anything, wed would be really happy if thar was such a function in the gamez for these types of messages in generalz.