I'm not venting, merely commenting on the illogic of the request. Illegals are not going to volunteer for a study of any kind, it's just not going to happen. My original statement on the subject was/is entirely subjective, based on my observation of the dramatic increase in the numbers of illegal aliens in my region of the country over this past decade.
How do I know they're illegal? Well, given that my understanding is that the number of green cards issued a year to new immigrants is somewhere around 50,000 and they come from all over the world, not just South America, I'm making an educated guess. Of course, playing into that is the complete lack of English language skills.