Server Privicy Varient

There is a button that allows you too "disallow direct message from ALL server".
If there was a button for example (like in the notifications that allow you to specify certain channels that you want to notify you) there should be a button that allows certain servers to direct message you.

how this would be useful. Maybe you are in a game server hosted by someone who isnt your friend and they want to contact you through direct message without sending a friend request