I have bought from Canada, had a shipping damage claim, it’s tricky, i.e. UPS Canada (different name) is separate from UPS USA.
but not dealt with what you are concerned about.
1. I would include an info packet inside the box. copies of original documents, receipt when new, evidence original taxes ... were already paid.
2. printed copy of repair estimate, showing it is going cross border for that purpose
IOW, unlikely event they try to tax you twice, they open it up, find the evidence you tell them is there.
3. you using original factory packaging?
4. put in a second outer box, i.e. shipping insurance requires ’double boxed’.
5. clarify who buys the insurance, i.e. whoever buys the insurance has to make any potential damage claim. going? returning? if maker buys the return insurance for instance.
6. have maker include your original info packet inside with their completed repair bill added to that.
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just to add:
Any seller who says ’local pickup only’, if you can get them to simply drop it off unwrapped at a local UPS office:
recently I pre-arranged with UPS: had someone simply drop off an unpackaged item to a UPS office I found near them. They simply told them it was for ... (my name). UPS called me with their price, took my credit card info, they package safely and ship.
UPS Canada was willing to receive in Canada, package and ship to me in USA, no hesitation.
