There will always be loopholes.
We need to address the source of the issue, and that's the Mexican border. Not only do illegal Mexicans cross into the US, but also Somali, Chinese, and all other sorts of nationalities. That's how the majority of them come in, through the Mexican border.
Since the federal government doesn't do anything about the issue, the states are trying to deal with the issue themselves, as they should. And if that means another piece of paper for citizens in Arizona, so be it. We are required to have ID on us while driving, entering a bar, et cetera, so it isn't that much of a big deal.
Just like that idiot Rangel said, "there is no border problem." Fine. That means the Federal government wants open borders AFAIK.