The NY Times reported Mexicans who once worked here with valid SS numbers, then returned to Mexico, actually rent out their SS numbers so other illegals can file with the IRS and pocket $3500 Earned Income Tax refunds.
A widely-used SS# scheme: the illegals name their anchor baby the same name as the parent. They obtain a valid SS# for the anchor baby; the parent uses it, no one checks beyond name-matching, if that.
CNN's Lou Dobbs reported illegals are stealing small childrens' SS# because a child doesn't use a number very often so it is near impossible to detect a stolen number.
Dobbs also mentioned that business owners give illegals SS# of a previous employee (it is not a felony to give away SS#s but it is a felony to use them).
I think that sounds more realistic than the claim of him being 28 years old.
The SS transfers happen most commonly with contractor type positions. Also with the section 8 housing. The homes get rented to a name, the people turn over happen every few months. But the names on the mail stay the same.