Once back in 1988, I was deigned entry into Canada because I had been busted for less than an ounce in San Diego in 1977. The fine was $100. The Canada border guards said, even though it was a misdemeanor in San Diego, it is considered a felony in Canada, and I would have to get permission from the magistrate to enter.
Now that Canada has better laws, I wonder if they would still deign me entry because of that 1977 event. I have always wanted to visit Vancouver.