Or, the pirates they are hunting actually sell their goods to someone who lives near those caves, and then a rock slide or something... Players are easily steered if they want to go in the wrong direction, the path has a tendency to bring them where they should be anyway. Threats are not really fun, unless it is to cause dissent within the group, you know, when one player has to do this, or he'll die, and the others just can't seem to care enough about that fact so they'll do the potential dangerous thing.