An unwritten law of the film universe, number 2

I have lost count of the number of times the main protagonist in a film returns to their house/hotel room/flat, only to find that the villain of the film is already waiting for them inside. So this means one of two things – either the villain has the ability to walk through walls, or the hero/heroine has conveniently left the front door or a window unlocked. And does so at the very time when they should be at their most vigilant…….I mean, why didn’t they change the locks? Answers on a postcard please to The Deep Focus, England.