Partly inspired by watching Home Alone & Home Alone 2 over the weekend (not my choice btw). I was asking myself how they were going to pull off the conceit that the same kid could get end up fending for himself exactly one year after he had previously had to. And his parents be unable to find/get in touch with/get someone else to find him. And he be able to finance himself lavishly. And (most amazing of all) the exact same villains from the first film manage to bump into him in one of the world's most populated cities.
Any other similarly ridiculously unbelievable film scenarios?