We drove all over the island on our scooter, not wearing helmets all the time. We never saw anyone use a helmet and the rental agency didn´t even offer one to us. It is just crazy and the final day that we had the scooter we were going on a short trip. We had a cheap scooter that only managed 60 km/hr so we were being passed by all the time. This couple passed by us on their scooter, not wearing any helmets, and when they were about 10 meters in front of us the guy lost control of his scooter and they flew off, sliding on the road surface. I was so close hitting them and we were all shaking. Fortunately they didn´t injure themselves much but their clothes were ruined and the skin on their feet and hands scraped off. It was a close call.
The moral of the story, use helmets even though its hot,