I'm going purely from memory here, so forgive me if I'm wrong:
A long time ago, somebody made the claim that certain areas (British Columbia?) might have an obscure law mandating a church trial by ALL CONGREGANTS as a condition of being legally established. I don't know what ever became of this.
The only major successful legal battle against shunning I know of involved a slander suit in which a lady got denounced by her rabid born again church for adultery. After this case, the Society got very strict about NOT announcing the specific cause of being Df'd.
There was some legal move to hit Df'ing in Brazil but I don't know how it turned out. Not much hope for hitting them in the US but you never know about a different legal system.
In the US, the way to hit them on Df'ing is indirect: child custody cases and attacking them in other venues whenever they come up with some 'poor us' persecution claim. Let everyone know how they break up families deliberately with Df'ing.
Unless they made some change (I don't have a Bible Teach book) the informed consent claim by the WTS is crap. It appeared possible to me to get officially baptised without any clear explanation of Df'ing.
IMO, the blood transfusion thing in Bulgaria ( "sans sanction") was the most blatant, deliberate and crafted lie the WTS has ever told to a governmental agency. And don't doubt that they were very embarrassed to talk about it.
metatron