Kids can be taught certain wilderness survival skills that will greatly increase their chance of survival if they are ever lost in the wild. I've found that these lessons can be fun and can be kind of a game when on hikes.
My first and probably best source for information on specific things to teach my kids about wilderness survival was Tom Brown’s Field Guide to Nature and Survival For Children. Tom Brown wrote a series of books about tracking and living in the wild and wilderness survival. At the very core of Brown's teachings is becoming aware of one's surroundings. Brown presents some games and exercises that help slow us down, make us stop and become aware of smells, sounds, the feel of the breeze. By becoming aware like this, one is less likely to become lost, as you begin to notice small things, noises, or an area that smells a certain way. It is also very important not to panic, and the idea of stopping, smelling, listening, looking around and thinking helps kids (and adults) not to make the situation worse. Brown states in his book that many people become lost within hearing range of a highway or town, but simply never slow down enough to realize it.
Children can also be taught how to leave signs for searchers. Tripods of sticks or piles of stones attract attention, and a message or arrow pointing in direction of travel can be left at the base of the sign. Also, if the child has found shelter, the direction to the shelter can be shown.
Shelter is an important concern, and Brown teaches several methods of staying warm and safe. The simplest way is just to stuff your clothing with leaves and debris, creating an insulating barrier. Even wet leaves will serve well in this way. Children can also be shown how to look for natural shelters and simple ways to improve the shelter. My kids love this, as it's like building a fort.
Water is an important concern, and this should be emphasized. Carrying water on hikes is vital, and children can be shown how to find the safest water available if the supply runs out.
Finally, kids can be taught how to stay safe around wildlife. If a child comes face to face with a cougar, the knowledge of what to do may save a child's life. The child should be taught to make themselves look as big as possible, raising their arms in the air, and making noise. Running is never the answer. Carrying a whistle can not only be a good idea to scare away animals, but can be used to alert search and rescue workers to the child's location.
There is much more than I can present here, but the important thing is, with a little knowledge and a few trips into the woods, children can become much more likely to survive being lost in the woods.