Some griefers hit the same camp twice, especially if they live nearby. If you intend to set up a permanent camp though, get yeomanry and put up a fence on your property, design your defenses so that players who want to steal from you have to pick up vandalism(50k lp!) and no new thief/grief will touch you. If you know people like this live nearby though, just leave if you don't have anything really important set up. If you don't have yeomanry, use a leanto and put the bed and a box in the leanto when you sleep.
It can always be good to get to know your neighbors too, they may even show you the ropes.