The workers that guide you along the way at the US customs line have no idea what they're doing. They greet you with "do you have a valid work visa for the US or are you a Canadian citizen?" So by that logic you can only be one or the other, lol? Sometimes they don't even tell you which line to go to as they are too busy chatting with each other and you end up going to the wrong line and waiting for hours unnecessarily. These people need some serious training or maybe they just need to put clear signs up so that they don't have to pay people to tell you where to go.