“When you get hired you must present a birth certificate or passport so they know who you are, ....”
With, it appears, one notable exception.
The folks without papers are not working on Wall Street that is for sure. They have minimum wage jobs at best. So yes if you want a job that pays 50K or more you had best show your papers, but if you want to risk a 15 dollar an hour wage than some employees may not ask for papers.