True! There are some that know the law and violate it anyways. And also there are some that are recent immigrants that may have less English proficiency and thus may have had troubles reading & understanding the customs form.

In reality, the majority of the travellers get away from not having to pay duties when they should have anyways. I mean unless it is something blatantly obvious, how can an officer determine if the bracelet you wore was purchased at home or abroad if the traveller has destroyed all the evidence (threw away the receipts and jewelry box before boarding the plane back to Canada).