And this is not just hypothetical. E. G. If you're crossing the border, say from Ontario where cannabis is legal, flying to California where cannabis is legal,

And this is not just hypothetical. E. G. If you're crossing the border, say from Ontario where cannabis is legal, flying to California where cannabis is legal, you can still get into enormous amount of trouble. A lot of Canadians are banned from ever going to USA again because of their misunderstanding or ignorance of the usa federal law.