Well, it's not that hard for people to look.
Should anyone really need a sign saying "Mind The Stairs."
It is already stated that the maximum hold is 100. And there is even a percentage counter which already tells
you when it is full.
It annoys me when I try to send a message and this happens, but it is their own look out. It upsets me but I rise above it.
It's not hard to look
and just delete a few.
But if you are
going to put this into action, Magister Ventrue, may I suggest a great big, bright green flashing star which fills the whole screen with the message "YOUR PM BOX IS FULL."
Perhaps a deafening klaxon could sound aswell. Something akin to either an air raid siren or a fire engine.
Then they might notice.