(I'm not sure where else to put this)
Basically, an example of this would be if a non-PvP Alliance player attempts to enter the Crossroads, a Horde settlement. Instead of being attacked/ killed/ flagged for PvP, said player will be teleported near the guards, who will be non attackable, similar to if a Alliance/ Horde player attempts to enter the Sunreaver/ Silver Covenant section of Dalaran.