To pull off the perfect crime one has to minimize risk while maximizing the yields. If you’re going to rob a bank you’ll have to put up with safes, cameras, random customers, polite staff and a quick police response.
So who is sitting on a goldmine but least expecting to get robbed? While not as expensive as more authentic melons, watermelons go for a rather high price in Japan. However, you’d have to be crazy to try and steal a bunch of watermelons… Right?