That's the point, the plugs and sockets are sort-of compatible. With a single market and freedom of movement this type of misuse is quite common and dangerous.

You struggle to plug any type of shuko/europlug/US/Austrailian plug into a socket in Malta or Cyprus, and vice versa.

Things shouldn't be safe when used right, they should be safe and not work at all the vast majority of times when used wrong.