When registering your copy of The Sims 3 Island Paradise, you will unlock the special “Tropical Waters Hat Pack“. Taken from the text cache of the site, here is the description.
Hat Tip: Valgon57
Congratulations! You have successfully registered your The Sims™ 3 Island Paradise game.
Download your Tropical Waters Hat Pack now to set a festive tropical mood! You can be the most eye-catching chica or chico on the beach with the towering fruit hat, or be the partay captain with the boat captain’s hat!