Its a different world these days.
Though the whole terrorist threat was likely the incentive for this thing, it looks like BC Bud is a big part of their scope as well.
"Smuggling is a two-way street," said Michael Milne, spokesman for U.S. Immigration and Customs Enforcement, part of the Department of Homeland Security. "We've got cocaine and money going north, B.C. bud and human smuggling coming south."
http://www.cnn.com/2004/US/West/08/20/bord...l.ap/index.html