Arizona's immigration law

V alerted me to the Supreme Court's ruling striking down parts of Arizona's controversial law.  Here is a news link. 

While I would like for the world to be free and open so that anyone could live and work anywhere, I understand this is not the reality of the situation and we are bound by the circumstances of our birth which results in our citizenship, or lack of citizenship, status.  It is hard to think of anything more arbitrary and unfair in the modern world's laws. 

Anyway, countries have a legal right to deport illegal immigrants.  If anything, living as a non-citizen immigrant in Europe has made me less tolerant of illegal immigrants in the US (I know that may sound counter intuitive).  However, we should have humanitarian limits to this.  The part of the law that the courts upheld, that police check the immigrant status of people they interact with, worries me.  This means that if illegal immigrants are being unfairly treated or taken advantage of they can not go to the police for help, much in the same way blackmail is used to prevent people from going to the police.  This makes illegal immigrants targets for extortion.  There should be an immunity clause where immigrants can not be deported as a result of going to the police for protection, to help solve this situation.