According to an article on nytimes.com: “The looser rules were reflected in sweeps like one conducted in New Haven in June 2007. During the raid, lawyers at Yales immigration law center said, agents who found no one home at an address specified in a deportation order simply knocked on other doors until one opened, pushed their way in, and arrested residents who acknowledged that they lacked legal status.”
With a new administration at the helm, it will be interesting to see the shift in US immigration and enforcement policies.