"As I understand it any new country joining the EU must take on the Euro the EU will not let Scotland get away with keeping the pound as an independent country as it would set a preceden"
    this could produce a similiar situation to ireland , where a whole black market exists, based around smuggling and trading across an economic border, what also happens is that people living close to the border, cross over to do shopping on the other side when the two currencies go up or down.