Sometimes on the Radio it will say that "[world] was nuked from orbit! It's the only way to make sure. Play nice everybody!" When this happens, it means that a world has been made inaccessible. The owner has been banned, and people in it may have been cursed. This is a good indicator to show that there is a moderator online. The world has been "Nuked", because of potentially illegal activity happening within the world such as a casino/drop game/containing offensive material.