I have no experience in the coaching world. My experience was strictly with Landmark.
Although they extract promises from the participants that they will not share what they heard from others in the training, it seemed to me that they themselves were very free with information about participants, and engaged in gossip amongst themselves. Also, they made use of information that participants had NOT shared with them, but that had been obtained in other ways, (for example, the participant might have confided things to their recruiter BEFORE doing the program, and that material was also "fair game").
Here is a post from someone who was in another LGAT - Gratitude Training, where that also seemed to be the case:
If anyone in the coaching world is operating as they do in LGATs, I would not trust them with ANYTHING.