Allow server moderators to "flag" suspicious users to have their posts automatically highlighted.

I'm one of the moderators in a fairly large server with over 1000 users, and we pride ourselves on keeping the server a clean and safe environment. It would make our jobs easier if there were a way to "flag" a user that has broken the rules in the past or otherwise acted suspiciously in order to have those messages highlighted, or linked in the moderator channel. 

It would also be useful if moderators were notified whenever that user posted a message, in order to ensure they are following the rules.