I think it has to do with the border but also with communications between Americans and Canadians that may involve e-mail correspondence or communications from individuals on both sides of the border. So it may be difficult, within e-mail correspondence, for instance, or within communications between a Canadian and an American, to perfectly segregate only the U.S. data from the Canadian data. Those are the kinds of complications that need to be worked out.
On October 28th, 2010. See this statement in context.