legally, yes. Of course, it's their prerogative not to sell them to you, and if you're a particularly large man be prepared for some flak from the counter staff... but yes, it's legal for you to walk into Shoppers and buy pins.
I managed to get them interested in a sponsorship at MuscleNexus.com, and their service with my shipment was spot-on, so I'm gonna try and give these bros as much positive press as I can!
Got my package today and like I said on musclenexus.com, they should seriously get into wrapping presents. Awesome wrapping. I wish I could hire them to wrap my xmas presents