New York City's welfare system routinely penalized recipients for infractions they may or may not have committed - or even known about. A nine-month investigation found the system - run by the largest welfare agency in the country - rife with arbitrary punishments and errors that led thousands of the city's most vulnerable residents to wrongly lose their benefits. The investigation found that the city sanctions welfare recipients at rates far exceeding other parts of the state. At least 75 percent of the sanctions challenged in the state's fair hearing process were overturned in 2012 and 2013. About ten percent of sanctioned recipients end up applying for entry to the city's homeless shelter system.