We don't do the Boss fights on our dedicated server... we do it on a private server that one of us hosts for the night. If you don't kill the bosses on your main world, then you won't get the raids other than the "beginner" ones which consists of Necks, Boar, and the occassional grayling. A decent fence or wall around your base will keep any of those from getting to your stuff. It's a "work-around" if you don't want to put workbenches all over the place or use mods.