It's funny. I sell mostly to the US. Nearly always, sellers refuse to pay the required shipping, they don't want to pay for tracking or proper insurance (or expect me to do it, which I reluctantly do, as I'm the one out the money if it gets lost) and yes, they nearly always ask me to underdeclare/mark it as a gift. Since we have to go to the post office regardless of where a parcel is going, it makes no difference time-wise.
It's especially confusing to me when they are selling things that only Canadians collect - but refuse to ship here and so end up with a lower selling price than they should have.
I rarely bother to ask some sellers if they will ship to Canada. I just do feel a bit sorry for them when I see things ending for low prices because I know I (and likely other international bidders) would have ended up giving them a much better final sale price.