Sadly, that tag IS invalid.
It is not part of the Toribash font, therefore it will show up as a [] looking box. Go ingame and make a room and type /cp < to check if the symbol is valid, or if you're playing, /em < will do the same.
BlackDemon: well i havent recived any warning or anyone telling me that its not valid.. so i guess its valid
and like i said everyone are our allies no need for invade tags . here its all about the love