Airline Passengers especially ones that are leisure travelers are extremely cost sensitive as noted with the sucess of LCCs in the US and Europe... I myself have driven from NW New Jersey to JFK (1.5 Hour drive on a good day) to hop on a Jet Blue flight to BTV simply because I did not want to pay $500 for a RT ticket on COEX out of Newark... However, if I was travelling on business somewhere I would choose the most convenient point of departure as I have because somebody else is paying for it...
With the whole border crossing thing getting to and from PBG I have a feeling since the US GOV'T has over $20 Million invested in this through the MAP Program (Military Airport Program) there might be an expedited crossing process somewhere down the road...