I was too, very early in the process as the elder that "trained me" was very open and direct once he thought you were making good progress. However, the words he used were very subtle. The understanding that I left with is that the person being shunned had committed a very bad sin, like killing or cheating repeatedly and unrepentantly. Even then, my understanding was that certain family ties were irrevocable. My wife referred the story of my brother in law who got married without parent and elders blessings. He got DFd and he left the house voluntarily. Wife insisted that he could have stayed and that no one would have quit talking to him. Which was true for her family but it made it seem like shunning was not that strict.
This, off course, was before many of the latter crazy push for shunning kids, or even those who talk against the organization.