Frenchy,
I've been giving a lot of thought to your example. I can definitely see where the dilemma comes in. After all, there is the matter of someone who is doing things that definitely bring reproach on the congregation.
I think Spec's suggestion about counsel is very good. After that time, however, I would suggest that the person's name be removed as a member of the congregation. An announcement would be made, but there would be no obligatory shunning.
Those who would feel uncomfortable being around this person would shun them on their own.
My main complaint about disfellowshipping is it's use for "sins" of a minor nature, such as smoking, or fornication involving teenagers. People such as these need help and support....not shunning.
I don't see any good that comes from obligatory shunning, other than to keep the current members from talking with someone who might give them information that the WTBTS doesn't want them to hear.
Severing the person's ties with the congregation would show everyone that persistent wrongdoing would not be tolerated, but a non-shunning policy would ensure that those who need support could get it.