Many people already feel the current compromising hard, without random foreign nobles getting a chunk of their messages. Don't underestimate some people's paranoia, despite their good will.
I'm not sure we understand each other. I was proposing that newly created characters get the realm-wide messages of the realm they are being created in. They're not random foreign nobles, they are nobles of your realm.
New characters don't appear out of the blue; presumably they just turned eighteen or achieved recognition as high nobility, but they were there before. They are going to receive tomorrow's messages; why not have them receive yesterday's messages?