Some dealers will do it who sell second-hand items (most of what I buy), and given that the import fee/taxes get more and more disproportionate, and arbitrary in amount, the higher the price goes, that is just as well.
When the fee can go to CAN $180 on top of a CAN $800 item, which is almost like 25% and makes no sense, second-hand dealers who won't under-declare are not worth dealing with. UPS will add even more of their own fees, so UPS into Canada should always be an absolute deal breaker (but is rarely offered anyway).
If the item is old, a dealer can decide whatever value it is supposed to have, so not under-declaring, at least a little, a used item that may be 30 years old, but is overvalued through name or rarity, is really pushing it.
Fixed blades, even double edged, are not a problem in Canada, fortunately. Except knuckle, D guards and push daggers.
Gaston