No personal experience, but a friend took their own kids plus some of their kids' friends into Canada. The border guard asked one of the little friends, "Does you mother know where you are?" The kid said, "No..." (which was accurate only in the hyper-literal sense that only children can muster), which then led to a delay while the guard called the parents to make sure everything was OK. Our friends laugh about it now, but it does illustrate the truth of the posting above that Canadian border guys take their jobs very seriously.