I have had this happen in reputable gun stores like Phoenix, Mil-Arm and P&D in Edmonton. I don't know the "law" on it per se, but yes- I've had the same thing, particularly when asking to handle Restricted weapons. In fact, Phoenix won't let you handle/ see a prohib from their case without the prohib class on your PAL.
By the way, it's good to hear Can-Tire in Red Deer and Calgary is still selling firearms. To the best of my knowledge none of the CT's in Edmonton still do.
Another reason to move to Calgary!