So I googled around, and found this conviction: https://www.justice.gov/archive/opa/pr/2008/February/08_crm_145.html

Justin Eric King, 27, of Chipley, Fla., has been sentenced to 41 months in prison followed by three years supervised release resulting from his conviction on charges of conspiracy to commit visa fraud, visa fraud and conspiracy to commit alien smuggling, Assistant Attorney General Alice S. Fisher of the Criminal Division and United States Attorney Gregory R. Miller of the Northern District of Florida announced today. The defendant and his co-conspirators brought illegal aliens, mostly from Bulgaria and Romania, to work in the hotel industry in and around Destin, Fla. King was sentenced by Senior District Court Judge Lacey A. Collier of Pensacola, Fla.

This isn't usually what we think of as "human trafficking." It seems that the people he smuggled understood what they were doing, and not being forced or coerced it. If that were the case, additional charges of exploitation would have been filed.