One of my friends brought her grown son and his girl friend to my place several years ago. After sitting on the balcony several hours (where we watched the boat traffic) they decided to go for a swim. We wrongfully assumed they meant the pool.
They proceeded to dive off the sea wall (not a good idea - it is shallow) and start swimming straight out towards the reef. No amount of yelling got their attention. Their mom ran down the stairs, across the beach shedding clothes and dove in. Thank goodness she reached them before anyone was hurt.
DUH! They planned to swim to the reef. I hear WAY too many people complain about the amount of boat traffic. I ask them what they expected. They seem to think the sea is just for their pleasure. I don't know how to reach people who do not have any common sense.