This thread contains some discussion about Canada border crossings. The emerging issues around marijuana questioning are proving to bedevil some border crossers. For those of you who haven't heard, Canada has legalized marijuana for recreational use. It's not clear to me what the U.S. authorities are hoping to accomplish by asking travelers if they have EVER used marijuana. The majority of Americans (52% reportedly) have tried marijuana at some juncture in their lives; the pertinent enforcement issue is not whether it has EVER been used, but is it being used at the point of questioning?
Anyway, here's a useful reference on that particular border issue:
https://www.cbc.ca/news/canada/saska...ewan-1.4884680