As a law-abiding United States citizen, I fully expected to pay duty and actually had U.S. cash on hand to do so. I said, aghast. I'm very unclear as to why the customs officer would not allow me to pay the required duty on my wine. There are many errors in the letters, too many to address here, but for the most part the writers are uninformed, misinformed, inflate their stories out of proportion, complain unnecessarily, and whine a good deal. If you do find yourself with an agent you are in deep trouble already and for good reason.
Inspectors are the same way.
They temporarily have control over you. Afterwards, you are in. Have your documents out and be ready to present yourself with your best foot forward. DON'T give them a reason to suspect anything, they are looking for those type of people. All Inspectors need is mere suspicion, not probable cause like police officers, to authorize them to further investigate, inspect and ask you questions.