In the U.S., some of the most successful headphone brick-and-mortar stores are the airport ones. When I'm traveling, I'll stop and browse in them when I can, mostly to see what the activity is like in them. When I stop in, I'm rarely alone in them, and most of the time I see people buying stuff.
Those airport stores would be fantastic for when there's on-location printing of customs. Like I said in
my post about United Sciences's eFit, I can see a time in the not-too-distant future where a customer will buy from their departure airport, and pick up the finished product at the arrival airport.
As easy as it is to learn to use the system--and as inherently safe as it seems to be--I think it very reasonable to expect scanners to find their way to
any store that sells premium headphones, like Apple Stores, Best Buy / Magnolia, Guitar Center, etc.