Are those who are accompanying or following others (e.g. a soldier with his commander or a servant with his/her sponsor/boss) and are fully unaware of the destination permitted to take advantage of the license to shorten the prayers?
If the people in question know beforehand that those whom they are following had the intention to travel, then they would be permitted to shorten. On the other hand, if they were fully unaware of the intentions of those whom they were following, they would be allowed to shorten prayers once they themselves set-off with the intention to travel apart from their companions. This ruling is the Hanbali and Hanafi opinion.