Could a foreigner visiting Canada or U.S states where cannabis is?
Could a foreigner visiting Canada or U.S states where cannabis is legal walk into a store with their passport to buy some? Yes. The only requirement is that you're above the legal age in that locale and have a valid, non-expired piece of government-issued photo ID to prove it. There are no restrictions based on residency and/or citizenship. Go ahead, partake and enjoy. Just don't try to take any of the green stuff back home with you.