I have a soft spot for totally arbitrary standards that achieve a security consequence. Here are three examples (driving, light bulbs, and handshakes). So I hear today that some thieves have taken to stealing a pair of shoes by grabbing the left shoe from the display in one store, and the right shoe from another store. Clearly the shoe industry just needs to standardize on displaying one, or the other.
Perhaps the thieves were students of civil procedure, and were avoiding federal jurisdiction for their crimes, under International Shoe v. Washington. The argument in International Shoe was that, because the people were only dealing with shoes of a certain foot (call it Left shoes, for the sake of my memory), they obviously could not have been participating in interstate commerce (the sale of pairs of shoes between states), and therefore, the federal government must not have had the authority to regulate their dealings.
So, if you only ever steal single shoes across state lines, perhaps you’re trying to avoid an indictment in federal court.
I know someone who worked for a security company in the UK in the late 50s, back then (some) left and right shoes were stored in separate warehouse locations managed by different security teams and only reconciled at the retail stores. Shrinkage was still a major problem and I gather that for the right fee the guards would collude to deliver hot shoes in pairs…