In a situation when a passenger of a scheduled flight leaving USA has something that has to be declared (like submitting FinCEN Form 105 for monetary instruments), what is the proper procedure for submitting the declaration?
As far as I understand, the routine departure procedure in US airports does not involve going through customs. But the instructions for FinCEN 105 state that the form should be filed "with the Customs officer in charge at the time of departure from the United States". So, where does one normally find that "Customs officer in charge" in US airports? Should the passenger simply inform the passport control officer that they need a customs officer? Or maybe passport control officer doubles as customs officer at the same time? Or should the passenger simply make an advance visit to some Customs Office in the airport?
Also, if an international flight out of the US begins with a domestic leg, what would be the proper location for dealing with the customs? Can it be done at the first airport? Or should it be done at the last US airport (immediately before the international leg of the flight)? Or, perhaps, can it be done at any US airport along the route?
In this specific case the route begins at SFO, proceeds to JFK and then out of the country. Both SFO and JFK certainly have Customs Offices. Does the traveller have a choice in this case, or does it have to be JFK specifically?