The rise in griefers has risen lately, and has happened mostly when I have been offline. The reason we have verified is to try and stop griefers from griefing while an admin is away. This technique is effective to a certain extent, but griefing still happens.
Now, to stop griefing, the admin who promoted the guest "must" keep on checking on that certain person quite regularly. I have been doing this, and has been proven to be quite effective.
So in conclusion, the admin who promoted has to check on the person every couple of minutes. Also, if the person sounds like a dick, doesn't talk, just flies around and doesn't talk, don't promote them. Use common sense when promoting.
-Vaon-