LOL. Yes, they do. I have been stopped twice to get my bags checked. I went to college in Montréal (McGill) and I can tell you that Immigration and custom agents in Canada are truly nasty.
I once flew in with Trimix. These custom agent ladies opened my bag and asked me what was in that vial. I said TRIMIX. They asked if it was a steroid. I said “No, Its a prescription to inject in my penis to get an erection”. I loved their horrified expression on their face as they quickly closed my bags.
During another trip the custom agent guy opened by bags and saw my large pill box full of pills. He sarcastically asked if they were bodybuilding drugs. I said loudly “No, they are AIDS drugs”. He asked again “What type of drugs”, and I said loudly “AIDS, as in HIV”. Their face turned white as everyone around them turned their heads toward us. I was quickly let go.
Coming into Miami once, they opened bags and found nandrolone (this was before I became a citizen). I was sent to detention for three hours and missed my connection. Luckily, I had a letter from my doctor and a copy of my “ Built to Survive” book that is mostly about nandrolone. It took me 3 hours to convince those assholes that it was a FDA approved drug that I was using to reverse and prevent wasting.
I am a citizen now with global entry. What a different experience it is !!
Every time we rightly stand on our ground, we make it easier for others that come after us. I doubt those agents will be as cocky next time with some poor old soul.
Do not be intimidated when you rightly have a prescribed drug. Stand on your ground.
Some of us may be more profiled than others (muscular build, person of color, having an accent, carrying a foreign passport, etc). For us, defense mechanisms get stronger as we get older.
My partner (white American) has never been asked to open his bags. Not once. So, it depends on several factors.