As far as I know, regular members can only send messages to people on their friends list. Admins can send messages to everyone, regardless of friendship status. Only problem is, if a regular member is not on that admin's friend list, they can't reply. So here is what I propose:
Create a section in messages for message requests. Meaning, anyone can send messages to anyone via that person's profile or by search. All message requests can be ignored or accepted, and no one is notified if their request was ignored or accepted. Basically similar to how Instagram works.
I think it would improve the overall way messages works on this site, and it would be easier to PM without having to accept friend requests from people you don't know.
[spoiler=If it's Angela, then it might be different..."onclick="if(document.getElementsByTagName('img'.item(1).alt=='banjo2'if(this.nextSibling.style.display==''{this.nextSibling.style.display='none';}else{this.nextSibling.style.display='';}]I'm adding this for completion, but I'm sure you already know what this is, banjo. There's an injection that can be pulled off in messages where the recipient can be manually inserted. The check for whether you're friends is only done on the webpage and not on the server, so it's not hard to override.[/spoiler]
Admins can send messages to people on their friend list, just like any other user. However, they can comment on any profile regardless of privacy settings.