Field Instances - Be aware!
Upon walking/running into Dragonhead, Sea of Clouds, and Western Highlands.. you will be presented with an option of which map to join. I.e. Sea of Clouds 1, 2, 3 or 4. Same for the others mentioned.
This is their way of easing congestion. If you teleport in, you risk not being in the same map as your party/gf/bf etc etc. If you walk, you can pick.
They will release a topic detailing which servers will have this feature implemented, and it is temporary. They will be monitoring if they need to add this to worlds not listed, and when they can safely remove it. They hope its not buggy etc.