Warzone does not process the event handler's return value.
Notes
The event only triggers once when a droid first enters it. If you want the event to trigger again in the future, you'll need to reset the area trigger using theresetArea()function (see example below).
You can define labelled Area objects at runtime and use them to trigger this event. For more information and example code, see: addLabel().
Example
Work out who our main aggressors are
// assuming we've labelled an area Foo
function eventAreaFoo(droid) {
// let's reset the area so it triggers again in future
resetArea("Foo");
}