In my opinion the children were a bit o relaxed because now they missed an opportunity to get rescued. One day the main character saw smoke at the horizon and I thought it was another island with civilization on it, but it was actually a boat. Already earlier I did not know why they did not make a signal to enlighten the recue fire. Therefore, they missed a big chance of to return home.
Another important point is that they were coloring themselves like Native Americans. I was trying to figure out the reason for this, but I think they just did it for fun.
In one sentence one of the children said “There isn’t no boat” and I thought he saw the boat because it cancel each other out, but he actually did not see the ship. Therefore, I am not sure if this is a type slang or a mistake in the book.