Everyone know and saw Raid Warning messages (text in the screen center). So i decided to write addon that will do same thing but inside guild. This is a very small addon without any settings. Just copy to your Addons game folder and forget. Filtered ranks will able to write important things as Guild Warnings. Everyone in guild must install it. Addon filters from both side so nobody can hack.
Setup: open LUA file and edit list of ranks (local Ranks = {"Guild Master", "Master"}) that will have rights to send guild warnings. Then give this addon to all guild members.
Usage: type "/gw YOUR_MESSAGE".
P.S. Addon was written for Odysseus guild.