I completely agree, PayPal is severely buyer-oriented when processing a chargeback.  Once, I even had proof that the buyer received the item because she left me POSITIVE feedback...but they were still dinks about it and froze those funds from my account for 2 weeks.  I am not a fan of PayPal, for many other reasons besides their procedures, but I do believe it's the lesser evil of NOT accepting PayPal (more n.p.b's "check's in the mail" -yeah right it is).
As I understand it, Canada Post offers $100 of insurance automatically on their parcels, whether the parcel has a tracking number or not.  So, if you send things overseas via Small Packet I know it doesn't have a tracking number, but they'll insure it for that amount anyways.  Just keep your receipts.  This is good for lesser-priced items.  My new policy is to never ship overseas anything over $100 (CANADIAN, not US$) unless it goes Xpresspost (which is EXPENSIVE.)  The other alternative is to just send it regular airmail, in which case you can add insurance over $100.  With Small Packet, you cannot purchase any insurance over $100.  Make sure you guys have at least filed your claims with Canada Post to retrieve up to $100!!
:-)