@set here = nowhere (or, to turn it off: @set here = !nowhere)
The NoWhere flag is settable on Rooms.
When set, no players in the room can be located with the @LOCATE or
WHERE commands. Players in the room will be shown as being *HIDDEN*
on the WHERE. If an @locate is done, the message "That player can't
be located" will be returned to the inquirer.
Pages will go through to NoWhere rooms.
Gods can still see the location of players in NoWhere rooms.