Wait.
So, if you got nabbed for a doobie in Canada, the USA has access to that information and denies entry?
It wasn’t an obscure document, it was a Canadian document. Some might say that’s a difference without a distinction.
But anyway, none of this “revelation” is any kind of news in Canada, we heard about it when the program started. There is also legislation that allows U.S. border police (agents, whatever you want to call them) to cross into Canada and perform their duties on Canadian soil — I think the arrangement is reciprocal but have never heard of a case where a Canadian went into the U.S. on a mission unless it was to get donuts and coffee perhaps.