I'm a firm believer in walkie talkies when people are in the woods. I bought several units at $10 each. I hope the scouts think of this. I know the terrain effects its' use but we have had darn good luck on our 100 acres of tough woods and its' an EXTRA way of keeping tabs on the grandchildren. We always tests the abilities of the user, too.
We have walkie-talkies, but the kids always leave them on and run the batteries down :-).