That's exactly what's happening and I imagine as people around the world hear that their might be amnesty granted to illegals they are making their plans to "vacation" in America right now.
It's really sickening to know that this many people have gone missing after their visas expired. They know that noone is going to come after them and if for some reason they do get identified as an illegal, no one is going to deport them.
This doesn't even begin to be just a Mexican problem. The next wave of terrorists are probably in this country right now after entering on student visas. Our government never even checks to make sure that they are even attending the school that they came into the country to attend.