How do you ship (untracked) for merchant fulfilled?

Hi,

I was wondering how Merchant Fulfilled Sellers are able to ship items untracked? Specifically for Canada. From what I see, if you sell an item you need to confirm shipment with Amazon. To confirm shipment you need to upload a valid tracking number.

BUT I see merchant fulfilled sellers do this all the time. They can sell for example a $15 dollar DVD and ship it out untracked. They can even send a shipping confirmation and estimated date of arrival to the buyers. All this without providing a tracking number.

How is this done??