Willravel

I can name a dozen from Mexico alone off the top of my head, maybe 25-30 from Central America. As a matter of fact, I've helped several of them study for the civics test, which is not by any means easy. Had I not had available to me resources on the test, I might have failed the test myself. And I'm no dummy. Even if all requirements are met, the odds of one of the 30 being accepted as a citizen are slim to none. Most of them have worked on visas here, and speak English well enough to make it in the US. The problem is that the education system in Mexico has let them down. Unless you're very rich or very lucky, you won't go to a decent school in Mexico. In addition to that, the same rich and lucky are really the only ones who are granted citizenship. If a border-hopper is lucky, he or she can marry an American, but that's not common enough to really help a fraction of those who need help.
You mean people from rich countries that vacation in the US or spend time here as a student? Why would it be hard for them?