It’s actually a good case study. It no longer makes sense to buy a fine watch from an American retailer. The tariffs incentivise a trip abroad. (I’m seeing something similar happen with skis.)

Not really. I’m bringing back a few thousand dollars of mounted, probably lightly-used, skis. Nobody expects to declare random purchases made abroad. Much less an article of jewellery on their wrist.

Hypothetically, one could simply wear the watch on their wrist on the flight home. Personal jewelry is not subject to duties.