Lack of sales tax is usually at the center of what they look at, but unfortunately, they forget the matter of import fees, as well as other things.
Imagine you get an antique diamond daisy ring when vacationing overseas. What you would not know is that the same jeweler probably owns the store here in, say, the Bahamas. Absent the need to worry about the kind of competition seen stateside, this jeweler can charge you whatever they wish. You would not know if they overcharged because comparing is not an option.
Some jewelers even take you out for “free” food and drinks, and then tack that price onto your bill, leaving you none the wiser. Looking at it, you would only notice there was no sales tax being charged. At best, you would end up paying just above store price. At worst, you could get swindled like nobody’s business, and still, remain an avid customer because you did not know better. So, no matter how warm and cozy your getaway, be wary when buying something as expensive as jewelry.