Quote: "No, no experience with the US customs in Ireland (that sounds weird)
Not weird, just normal American arrogance to have their government agencies operating openly in other countries. Do these subject countries have no pride that they let their sovereignty be usurped?
The subject countries should evict these American government operations. Flights to and from the USA should be no different from flights to and from other countries. If the Americans want to get difficult then impose counter-vailing duties and similar retaliations. A few years ago when the yanks started getting nasty they required all visiting Brazilians to be finger printed. Credit to Brazil for promptly requiring all visiting Americans to be finger printed! If they can do it then so can American vassal countries such as Eire and Canada.