I Germany there is a small island called "Helgoland". It has like 10 inhabitants and can only be accessed half a day (tide). BUT they have their own zip code.
I have this zip written down in by purse and in the case a German retailer were to ask me for my zip I'd give that zip to them.<p>This prank is called "Ein Supermarkt für Helgoland": Trying to make them build a supermarket on that island based on the supposedly demand that people from Helgoland's zip code need one on their own.