Region crashing
From NSwiki, the NationStates encyclopedia.
Region crashing is the process where a group of nations all move to a region with the aim of seizing the UN Delegate position. Often, after gaining control of the delegacy, any nation approaching them in endorsement count(and almost always all defenders) are ejected. (But not banned--see Griefing.)
People who participate in region crashing are usually called raiders, crashers, or invaders.