Send them out with radios or flashlights that have almost dead batteries, as this is the way it usually works. If it was a rainy when you send them out all the better.

Have the person that they are looking for hide, I have a book on outdoor survival by Wayne Fears and he has been involved in lots of S&R operations and he says in the book it’s common for kids to hide from searchers. It seems they are afraid of getting in trouble, so they hide.