Winston, so we're on the same page, I don't think we're talking about jump-shot scenarios where combinations also exist. For the sake of this thread, let's assume the shooter is obstructed by a cluster.
With that said, if the obstruction is slight and only a small jump is needed to pocket a relative hanger, I don't think you'll find a player in the past 60 years that will not take that jump shot. On the other hand, if the shot requires jumping over an entire ball and/or the object ball is not hanging near the pocket, it would be regarded as foolish then and now.
Personally, I would rather not see jump cues used in 14.1 because of a number of reasons but most importantly because 14.1 has the game's most cherished record - 526 consecutive balls pocketed. In my humble and personal opinion, in order to break this record, one would have to do so with the same exact cue for each and every shot which is a player requirement as opposed to equipment requirements which players cannot control (ie., size of table, size of pockets, etc).