Now that gnome-terminal (also mate-terminal, etc) no longer registers as a login session, what is the mechanism for sending messages to logged-in users? This is fairly important for shutdown, "UPS on bettery", etc. messages. The "wall" command does send a message to plain console sessions (Alt-Fn consoles), but the message does not reach GUI users whether or not a terminal emulator session is active, even with a terminal session started with the "Run command as a login shell" option selected.