Feel free to try and bring it in. But bw022 already gave you the answer, and you dismissed it as wrong.
You claim the knife is legal because it is not a switchblade, it is spring assisted. But the law specifically states (and I will highlight the words)..."PROHIBITED WEAPONS include any knife that has a blade that opens automatically by gravity or centrifugal force or by hand pressure applied to a button, SPRING or other device in or attached to the handle of the knife..."
Even Wild Bill's website specifically tells you to be careful if you are a Canadian customer: "...Some of the items we sell may not be allowed into Canada. It is your responsibility to know the laws of your area before placing an order. We are not responsible for any items that do not clear or are seized by Canadian customs, and no refunds or allowances will be made..."
So here are the three things that could happen:
1) Nothing. Maybe your knife is legal and you get the package and only have to pay any duty or taxes on it.
2) Your knife is seized by Canada Border Services Agency when it arrives at the customs office. You lose the $5.25 plus $13.95 Shipping and Handling.
3) You are found guilty of trying to import or posession of a prohibited weapon into Canada. If you do so and you do it "knowing that the weapon is prohibited", you can be found guilty of a federal crime and face a minimum one year prison term if the crown chooses to indict you.
http://www.parl.gc.ca/Content/LOP/ResearchPublications/prb0553-e.htm#afirearmsoffences
I would look at it this way...Are you able to find a similar knife in Canada to the one you want to buy from a website in USA? If the answer is no, it's probably because the knives are illegal in Canada, not because they don't want to sell them here.