SSI fraud is very easy to get away with, and there is a whole subculture in the inner city that promotes this fraud. Social workers get bonuses based on efficiency, which means making sure as many possible recipients get benefits.
The last stanza of the old Creedmoorer niggun:
Foodshtemps, foodshtemps, nit nor far Yidden
Foodshtemps mit velfare, iz shtark tzi freeden
Foodshtemps, velfare mit ochet Section-Eight
Far SSI darf tzi machen tzi drayt
explains it all :).