I am 99.99% certain that no electric regulation code (in US, EU, everywhere) allows "contacts touching screws" to be called proper connection method. I would throw out such thing immediately if I found one in my property.
Also, such socket design is pretty poor and very dangerous. All it takes is one screw to go missing/unscrew/break, then one can touch exposed and unshielded (!) live screws from the sides and electrocute oneself. Am I the only thinking this is crazy?