This story rather speaks for itself.
But a few observations:
The sgian dubh is not a prohibited weapon: it is a part of ceremonial Scottish dress. The analogy with Sikhs and their kirpans (already legally decided, by the way) is rather obvious. Carrying the sgian dubh in this fashion clearly meets the “reasonable excuse” requirement.
The small knife was unconcealed. It was not being brandished.
The Montreal police are notorious for throwing their weight around. Here is another glaring example. (The citations against Amal Asmar, for sitting on a bench while Arab, were eventually dropped.)
Perhaps worthy of mention is that the people targeted in both cases are not white. (The bagpiper’s grandmother was Scottish. He has a Jamaican mother.) Racial profiling is a well-used implement in the Montreal Police bag of tricks.
Should Jeff McCarthy choose to complain, well, good luck with that. We can hope that he gets his little knife back, at least, without having to pay into the coffers of the City of Montreal for the privilege of walking while Scottish.