All of the Fun, None of the Responsilbilty

We had a interesting family outing at Winter Island the other day. We walked around, looked at the boats in the harbor, saw the little fishes swimming around the dock, had a picnic in the camping area, and eventually walked along the little beach there. All was well until the twins decided to get a little adventuress. As usual, the twins worked out their ruse together. Lucy dropped her stuffed bunny, in order to keep her mother occupied. Ellie, in her father's care, was squirming in his grasp, so he put her down for a moment and turned to ask his wife a question. A second was all it took for Ellie to bolt sideways away from the group and ran into the water. Lucy did the same but ran the other direction. Seeing that there were four adults, we broke off into pairs to chase the little ones down. Ellie got in the water the farthest. She was in up to her armpits before Theresa ran into the freezing water to get her. Needless to say, both were soaked. Til fared little better, Lucy didn't get in as far as her sisiter, but still was pretty wet.

Both parents were soaked,shivering, and fuming. The twins were happy, giggling  and no worse for wear. And what were their grandparents doing while this was happening? Nothing but sitting on the beach, dry and laughing. Why? See the above title.