Got looked at by customs years ago when I bought a ring onboard. That was just about the only purchase and even with the souvenirs didn’t even go above 1 person's limit. Another time I declared a purchase from I think St. Thomas jeweler that was being shipped from the jeweler's manufacturer in the US. Customs wanted a form, which we didn't have, or even knew about. At one point I asked if they wanted me to get back on the ship, return to the island to get the form! They searched, found the form, we filled it out and were on our way. Felt sorry for the porter that stuck with us.