Mine usually do say Canadian, but I've gotten a few (like the MAC & Milk) that have specified US only, so I've never tried to use them.
Before posting this thread, I never considered that it might be an error. Perhaps they are accidentally sending the US email to the Canadian list without editing the footnotes. It's common for companies that operate within the US & Canada to share marketing materials (although they usually edit the materials to apply --- color becomes colour, etc).