As a second point, I don't really support what you suggest tesfanner; as a starting point it wouldn't prevent the griefing from happening - if someone wants to play we can't deny them access on a baseless suspicion that they may grief, and once they have griefed it's not very difficult for me to stop them entering the server again, it just requires me to wake up and check the logs for their IP. I think we should keep it nice and accessible; especially considering people have the be approved to play on the server anyway, and thus can be freely and permanently removed.
[edit]: there seems to be some sort of Hamachi problem; try and restart hamachi on your sides, and I'll play around with it here.