I wonder how common it is for someone (especially a young person) to commit a disfellowshipping offense (such as premarital sex) and just fade away from the congregation for awhile, becoming inactive (and "worldly") out of guilt. Then to resume activity, perhaps in another congo, resolved to follow "the truth" yet never having faced any organizational discipline for the offenses leading to, and during their inactivity.
I know someone who did this and have read about others who have done this. It's just another example of how any human system of discipline is imperfect and as such, should not claim to have any bearing on a person's status before God.