Yes, they have to fill out the I-9, but so what? You can lie your ass off on it and it takes 6-10 months for the government to even notic and send you anything back. I turned a guy down because his documents were so badly faked it hurt, and two days later he was back with a nice, shiny new ID, WEARING THE SAME CLOTHES HE CURRENTLY HAD ON! By law, you HAVE to accept them.
How come Visa can make a fraud-proof, hologramed credit card, and yet the best the US Government can come up with is a typed Social security card on crappy paper that can be faked and printed out in 10 minutes?