Re your sig line, I think Schengen doesn't matter: there is a border domino in this refugee crisis and the re-imposition of intra-Schengen borders will only result in more dominos falling.

• The first domino was the border between Turkey and Greece. Already three years ago, Greece built a border fence. This only resulted in two things: most migrants took the sea route, and Turkey ceased any efforts to control departures. Greek refugee camps over-flowed, and Dublin III was voided for Greece.
  
• The next domino was Macedonia, where the scandal-ridden and aggressively autocratic government decided to send down the army a few weeks ago. This only resulted in a log-jam, and the crowds broke through.
  
• The next domino would have been Serbia, but Serbia was greatly angered by Hungary's border fence, so it is providing free passage now.
  
• Everyone saw how the next domino, Hungary, fell.
  
• Should Austria re-impose border controls, the refugees and smugglers will be able to spread out along a winding 366 km section of the former Iron Curtain, with lots of woods on hilly terrain and almost no rivers to cross. Methinks that domino would fall rather quickly.
  
• The border of Germany and Austria is a bigger challenge, being mostly high mountains or wide rivers. But closing this border might result in refugees massing at a few border crossings, resulting in situations like at Budapest Keleti.

_{*Lunatic*, n.
One whose delusions are out of fashion.}