hmm then I guess it was the way I thought about it.
Now being a brit here in the US, I do know that I did go through customs on the way in, but not the other way. The reason for my assumption was due to when I worked for a tech selling company, people leaving the country with goods would have to go through customs to declare it and get their tax back from the Chamber of Commerce of the goods purchased.
Again, it was my interpretation... so I guess we are talking about something different?
Forgive my ignorance on this subject

still learning...