While it's illegal to hire undocumented workers, there's nothing wrong with lending them money – in fact, federal and state governments are actually encouraging banks to issue home mortgages to illegal aliens.

Foreigners who are not eligible for Social Security cards can apply to the IRS for an individual tax identification number (ITIN) enabling them to pay taxes. About 8 million ITINs have been issued since 1997 – and an ITIN can be an illegal alien's ticket to a home mortgage.