Not notified when the terrorists or cartel come walking in either.
Check it out:

A Homeland Security Department official testified Friday before the House Homeland Security Subcommittee on Border and Maritime Security that U.S. authorities are not “routinely” notified when foreign sex offenders enter the United States.

“We can receive information on foreign criminal records, and in fact the NCB (National Central Bureau) is the vehicle through which 190 countries can communicate, and there are … registered sex offenders, but routinely, that information actually would not come unless there’s a specific case or a specific law enforcement inquiry,” Alan Bersin, Assistant Homeland Security Secretary of International Affairs and Chief Diplomatic Officer, told the subcommittee.