Originally Posted by GUWonder
If she presented a then-current valid Chilean passport to Chilean immigration control authorities on entry into Chile, she could also show it to Chilean immigration control authorities on departure -- after having used her US passport to check-in for the return Chile-US flight. Thus, there would be no $100 visa reciprocity fee applicable as there would be no entry/exit stamp matching. And upon arrival back in the US, she presents her US passport for re-entry into the US.
The Chilean in question currently has an expired Chilean passport; and getting on a flight and entering a country using an expired passport is not advisable.
Let's say that the passport got renewed. If she enters/leaves Chile using her current valid Chilean passport, at departure she would be required to present a visa to enter the US (as she's presenting her Chilean passport, not her US passport). That's what I'm trying to get at..