I'm not sure about any laws, but we've spent quite a bit of time there. I've never seen a carseat in the Bahamas, except for the one we brought with us... It's a very laidback country. If she just takes her normal seats, then that will be fine. If they're going to be in a taxi, then there's a chance some taxis won't have seatbelts. But she can always wait for one that does.
ETA: After posting the above message, I looked it up. Here's a
link to a law:
Where any passenger mentioned under this section is under the age of five years, such passenger shall be secured in a child passenger seat positioned in the rear passenger seat of the motor vehicle.
But we were just there last year for several months: children were hanging out of car windows, etc. Even if the above was actually made into a law (which wasn't clear...?), it's not being enforced. Regardless, the laws of physics still apply. Just do what she does here and she'll be fine. :thumbsup: