My parents were in Banff last September. When they crossed the border to get into Montana the border patrol asked if they could prove they were U.S, residents. My dad showed the border patrol a MN driver’s license. The patrol told my dad this does not prove you are a resident, only that you can operate a vehicle. The patrol did tell them that in 2007 they would need to prove residency to get back into the U.S.. Maybe the Border Patrol was confused on flying vs. driving, but we are telling everyone in our party to have a passport this year.