I agree that many OOT bag items are things people bring anyway or things that are free in hotel rooms, and that local flavor is way better. I also agree with MarieSam that it would require waiting until you get in town to get the local items and she's right, time flies and things are hectic enough once you get there.
Say you have 50 guests...think of getting in town, going shopping, and lugging back 50 bottles of rum, 50 cakes, 50 bags of coffee, 50 mugs, etc. It's not impossible but it makes for a lot of work when you could be visiting with your guests or relaxing before the wedding.
In ours we included things like dominoes, cards, waterproof neck safes, etc. that people enjoyed and didn't bring with them. A mix of fun and local is great if you can work it out.