That is never going to happen.
Shunning is less harsh now however. But people fear the disgrace of getting df, the announcement and a df person cannot recover completely from it because it will always be part of his history record if he returns and what he did is also recorded and known. Fear of shunning keeps people in line.
Before becoming a JW, a person needs to decide then because shunning is part of what a person subscribes to when he joins and is a accepted as fellow: You marry the woman, take her home, sleep with her, then later on you change your mind and want to dump her and move on. Now wait a minute, why did you marry her to begin with. Why did you sign a contract before first reading it or why did you agree to its binding terms and now you want to back out of it without the other party having the right to enforce the terms you agreed to when you signed it.