Very interesting read from Federico. And I am happy to say one of the complains spotted in that doc:
It would be nice if there was a system-wide notification option, so we could send /etc/motd to every user logging in
An application like kwrited. No, seriously, GNOMErs on my company don’t get notified by shutdown +nn or wall unless they have open terminals
It seems pretty trivial to me to add that to the motd implementation and use the same notification mechanism.