It's easy to forget that the corollary to Schengen is that police can ask for your passport at any time anywhere. I remember this was a big issue in France when it started out, because people were claiming that minorities were being excessively targeted by the police.
Which is why I don't understand the problems with the AZ law, a law that is basically in effect in Austria and most everywhere else.
It violates constitutional provisions related to search and seizure; a cop isn't allowed to ask to see your passport without a good reason. Do those protections exist in Europe?
I'm no law expert, but I'm pretty sure that the Austrian Foreigner Police can ask ANYONE for a passport. Foreigners are mandated to carry a passport with them ALL the time while in Austria. And I have seen numerous newspaper articles which read: "During routine checks by the Foreigner Police in trains, police officers arrested a man/woman from Afghanistan/Iraq/Kosovo etc. who had either no passport with him/a negative asylum decree/or a denied entry by law. They were taken into Schubhaft (arrest awaiting deportation)." Most officers are probably just saying: "Hey, the guy looks foreign, let's check him".
Hmm, I never carried my passport while in Austria. In reality though, I doubt Americans are really susceptible at all to deportation or harassment by cops; they know we're here to spend money and not blow things up. I was travelling with a Chinese national and the Austrian border police spent a considerably longer time analyzing her passport than they did mine or any of the of other Americans in my entourage. The Icelandic border police noticed my foreign appearance, grabbed my bag and started to put it through their x-ray machine, but then saw my American passport and promptly handed my bag back to me without even analyzing its contents.