I've been 3 times in the past year- once to Toronto, twice to Montreal. We drive into the country, and then fly out to Europe. I don't have a link to it, but Health Canada does make a provision for non-citizens to import small amounts of what they consider to be "prescription" products for personal use. So, it's legal in that respect, or at least it was the last time I checked (a year ago).
We've never had an issue. I DIY and don't label my juice. I've debated that one.. but just leave it alone. No one has ever asked a single question about our gear or liquid. I don't advertise it, or make a big show of anything. We were allowed to vape openly in a quiet corner of an airport cafe in Montreal. No problem. I LOVE Canada.
I always have a backup bottle of juice in my checked luggage, or send a bottle to my destination so it's waiting for me when I arrive, but I've never needed to touch it. It's pretty rare these days to have your luggage searched flying into a country. Although the last time it happened we were searched by American customs when we were transiting through Toronto. Americans search, but I haven't been searched arriving in any other country in a very long time.