I have no idea what duty/licensing/legal stuff is involved in selling/shipping to Canada, but I do know that when a box of papercrafting supplies cross the border destined for a scrapbook store the duty is astronomical. Store owners must transfer that cost to the product and that's why it's a little more expensive up here in the stores. That being said, isn't shipping to Canada from Stampin' Up! like other online stores that ship to Canada: WE are responsible for the duty etc. when we get US goods?
Your question is the reason I haven't purchased SU! in 4-5 years. I can get great products at my LSS for a heck of a lot less than the inflated prices PLUS shipping. (And I'm supporting a family-run business in the process)
I design for: Stampendous!, There She Goes, Technique Tuesday,
SRM Stickers and Deconstructed Sketches.