I'm always willing to add in some useless and potentialy wrong trivia to a topic like this - back in 1985-87, there was and probably still is a ban on the importation of switchblades into the US, however a one-armed person could legally import switchblades for personal use. I remember reading the reg, and was so pleased when the T/F question actually appeared on the customhouse broker's license examination the year I took it.

The other good bit from that exam had to do with cattle that roamed across a free range border were not considered illegally imported. I could imagine a smart rancher setting up his operations uphill on the Canadian side, and letting his cattle go down to the slaughterhouse under their own power.

There is the apocryphal and probably wrong story about my grandfather, who made it part of his business to import whiskey during prohibition, by rolling barrels of the stuff downhill from Canada somewhere near Buffalo. But I already digress from the switchblade topic...