I’ve had experience carrying several watches from Canada into the U S, several times in the past. On one occasion, the agent asked me to show the watches to his fellow agents, on the way into the U S. Following that, they wished me a safe journey, I packed up the watches and was on my way.
On another occasion, different border crossing, I told them I was carrying watches (including several Rolexes), and was asked (told) to exhibit the watches. The boss poobah seized them on the spot! Informed me that “fake” watches were not permitted for import into the U S. (There wasn’t a fake among them)! He demanded that I prove they were genuine, or in 60-days, the watches would be melted! Long story short, after paying a huge duty on my watches at a nearby broker, I returned to the crossing to be told that, under NO circumstances were fake watches permitted. He phoned someone, somewhere, and finally allowed me to return to Canada WITH my watches, leave them behind, then return. I drove 35 kms back into Canada, rented a box at a bank, deposited the watches, returned to the border. Same guard asked if I had left the watches behind, then wished me a good holiday!
In short, on a good day with the right person checking the contents, you’ll be okay. On the wrong day………..! The laws exist, it’s just a matter of whether they’ll be enforced with your item!