This is a story—or a fact really—that for some reason gives me great delight.

I’d always suspected that the following observation was apocryphal, but apparently it’s really true: actual pickpockets tend to hang out near “Beware of pickpockets” signs. Because, it turns out, when people see a sign on the street or in the subway that reminds them to “beware of pickpockets,” the first thing they do is to check their pockets, their purses, their watches, their jewelry to make sure that their most valuable possessions are still safe. And in this way, they signal to pickpockets exactly where their valuables can be found.

This little story shows the inexhaustible ingenuity of mankind! And about how we should always be on the look-out for unintended consequences.