Disable-builtin-messages
From FreeSpace Wiki
Disable builtin messages (Action operator) Turns the built in messages sent by command or pilots off Takes 0 or more arguments.... If no arguments are supplied all built in messages are disabled All: Name of ship to allow to talk.
Comments
Just like the name suggests, this SEXP is intended to disable builtin (allied/enemy arrival, traitor, critical damage, praises, etc.) messages sent by wingmen, Command, or AWACS vessels.
This SEXP is the exact opposite of enable-builtin-messages.