I have a feeling that the crossing guards would be more understanding of bear spray at the AK/YT border than the 49th parallel.
Like Dwayne said, you can buy it in Canada. You just need to show ID and sign a log book as it is semi-controlled.
SS
"To be glad of life because it gives you a chance to love and to work and to play and to look up at the stars. To be satisfied with your possessions but not content with yourself until you have made the best of them." -Henry Van Dyke
