The Globe and Mail reports in its Saturday, July 21, edition that if you admit to smoking marijuana, or if you invest in or do business with a U.S.-based cannabis company, you could be asking for trouble at the United States border. The Globe's John Heinzl writes that Canadians can and do get barred from the U.S. for so much as admitting that they have used the drug. It is not just drug users who are at risk. Canadians who invest in a U.S.-based marijuana business can also run into major problems at the border. Sam Znaimer, a venture capitalist in Vancouver, was trying to travel to the United States in May when U.S. agents questioned him about his investments, which include interests in the U.S. cannabis industry. He is now barred for life from entering the United States. Canadians who are barred can apply for a temporary waiver to allow entry, but the process can take up to a year and the waiver must be renewed periodically. Len Saunders, an immigration lawyer in Blaine, Wash., has recently seen a spike in cases of Canadians who were denied entry to the United States or barred permanently because of direct or indirect business ties to the U.S. cannabis industry.