A vehicle registration plate is required in all countries, for official identification purposes. So if you somehow lose them, they get damaged - or stolen, you have to get a new set. How would you do that, though?
Most people would probably just order replacement plates, but some people probably don’t feel like going through all that trouble. Someone thought it would be a good idea to just ‘do it yourself’.
The handcrafted cardboard plate with letters and numbers scribbled on with markers totally fooled me, but unfortunately the police in Hopkinton, Massachusetts weren’t really convinced. Turns out this was not a good enough replacement for a state-issued plate.