The law is quite clear: non-Jamaicans (meaning no Jamaica passport) have to declare anything that is not solely for your personal use and will stay in Jamaica when you leave. All the details are at the Jamaica customs Web site.

Do people routinely smuggle stuff in? Yes. Do they ever get caught? Occasionally. Mostly nobody searches luggage in the "nothing to declare" line. If yours gets searched and the customs person is up for it, you're going to have a hassle.