The Jacksons regularly receive wrong-number calls for Sara, whose phone number was misprinted in a directory  Sara contacted the Jacksons, informing them of the misprint and her correct number  The Jacksons did not lead Sara to believe that they would pass along the correct number, but it would be helpful to Sara and of no difficulty for them to do so
Thus, although it would not be wrong for the Jacksons to tell callers trying to reach Sara merely that they have dialed the wrong number, it would be laudable if the Jacksons passed along Sara' s correct number
If one can do something that would be helpful to someone else and it would be easy to do, then it is laudable and not wrong to do so.