Thanks for the introduction, Gazzawazza!
EU law requires all member states to admit anyone who can prove their citizenship of any other member state (by producing a valid passport or national ID card) throughout the validity period of that document. Since you're never obliged to leave any EU country (as you have the automatic right to live and work there) it would be impossible for any country to make a regulation based upon your departure date.
Incidentally, passport controls have been almost completely abolished across the whole of the EU. Anyone can move freely between any two member countries without the need to present either a passport or a national ID card. (Airlines might require photographic ID but that's completely separate to passport regulations). That applies to non-EU citizens, such as Americans, Brazilians or Iraqis, just as much as it does to EU citizens. Out of the 27 member states only two countries have yet to abolish passport controls for inter-EU travel. The UK refuses to do so. Ireland would like to do so but can't unless it closes the currently open border between the Republic and Northern Ireland.
Chris