Weed is legal in Canada. Last I checked, and it was certainly true when weed initially became legal in Canada, marijuana is still very illegal in the US, federally.

So your VISA, Mastercard, or debit-backed-by-a-US-reachable-bank records can show you've been purchasing what the US Customs officers see as a highly illegal drug, and you potentially lied about it the last time you said you didn't.

Depending on your ties to the States, like family, property, transiting across the border each day for work, or just an annual holiday, I would count that as a disaster.

But I'm sure the US would never... /s

https://old.reddit.com/r/canada/comments/9hhkxw/us_border_of...