They accused Wal-Mart of trying to clean its stores “on the cheap” by paying contractors it knew hired illegal immigrants, who might be tolerant of lower pay and unfair work conditions. They added they were coerced to work by threats to report their immigration status to authorities. The plaintiffs said that, while Wal-Mart was not their direct employer, it exercised control over their activity. Often, they said, Wal-Mart locked them inside at nights and on weekends to prevent theft and keep federal agents from finding them. […] The 3rd Circuit rejected the false imprisonment claim, saying Wal-Mart offered evidence that its stores had unobstructed emergency exits.
http://www.reuters.com/article/2012/08/09/us-walmart-janitors-idUSBRE8781CZ20120809