If EU needs to scare its members to show how badly a leaving member would be treated, it's no longer a union of consenting, democratic members. It's not the union that I voted to join, a union that works for the benefit of member countries under guidance of their respective governments for free trade and co-operation; someone started to build an empire and is now mightily pissed off as some people don't want to be in an empire but just have a free trade union of independent countries.