Then it is Arizona's problem. If a local officer decides to bug Hispanic citizens using this law, then it would be a violation of their 14th amendment rights, Section 1.
Section 1. All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.
The state would be sued, lose a lot of money and the law would likely be overturned by a high court. As such, it falls on Arizona to train their local law enforcement to be very careful about who they question.