Quote Originally Posted by Causality View Post
Depending on each World's congestion, there may be Worlds that do not separate areas into Field Instances. Please check the "Worlds Currently Using Field Instances" section to see which Worlds are currently utilizing Field Instances.

Those worlds are automatically going to start with the instances and other worlds will use them as the need arises. I imagine they have an instance cap which will automatically trigger the initialization of the field instances.

Two games that use this on the top of my mind are Elder Scrolls online and Star Wars the Old Republic.
SE is not famous for having such automatic systems in place without a 3-6 hour emergency maintenance.