Yes, same thing with registered mail. USPS only insures up to $25,000, so many mailers go only to that value. But if the article being mailed is worth $250,000 and it gets lost/stolen/damaged, the mailer can only make a claim for $25,000

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For what it's worth, Canada Customs look over articles very carefully. I've seen many registered articles being returned from Canada when fraud is suspected...
East Hill