There are a number of peculiarities about how Jehovah's Witnesses do things that may or may not be relevant legally.
They haven't properly defined what constitutes membership in their organization. The baptism questions are worded in a way that implies that baptism is what makes someone a Jehovah's Witness.
This is peculiar because when someone is disfellowshipped, it is announced that they are no longer one of Jehovah's Witnesses. It would almost seem like their baptism has been invalidated. Yet, when they are reinstated they aren't required to be rebaptised.
So was the baptism valid during the disfellowshipping period or not? If the disfellowshipping invalidated the baptism and membership in the religion, then a person who is reinstated and not rebaptised could claim that they have a right to sue if they experience any further disciplinary action. The person wouldn't actually be a member if baptism is what defines membership. (At least that argument could be made.)
On the other hand, it could be argued that disfellowshipping doesn't invalidate the baptism. In that case, someone who has been disfellowshipped and is seeking reinstatement could be viewed as a current member who is experiencing congregational discipline. He will be harassed by the elders and will maintain communication with them. He will be shunned by other members and have to endure a shaming ritual as he attends meetings on a regular basis. If he succeeds in ending this period of congregational discipline, he will not have to undergo a new ritual (baptism) to indicate that he is one of Jehovah's Witnesses.
If that person becomes dissatisfied with how he is being treated and sues, then the Watchtower lawyers would probably claim that this is an internal religious matter and that the courts have no jurisdiction. And they would have a point.
However, if such a situation is truly an internal religious matter, then the announcement that someone is no longer one of Jehovah's Witnesses is a lie for those who have been disfellowshipped.
If that announcement is a lie, it could be argued that it is just code for the idea that the person is still under their control and it is proper to continue to punish and harass the person until the elders say it's time to stop.
In that case, such an announcement would be morally reprehensible if applied to one who disassociates. It could even be problematic from a legal viewpoint if someone found a way to challenge that in court. (This is just an opinion from someone who isn't a lawyer.)
What if baptism isn't what determines membership? It is noteworthy that Jehovah's Witnesses don't use baptism as the criteria for determining the size of their membership. They only count people who share in their ministry. This includes people who haven't been baptized yet and ignores those who have been baptised, but are inactive.
If their ministry is what implies membership (as their name implies), then they have a problem. It resolves certain inconsistencies about baptism, but it implies that anyone who has become inactive for a significant amount of time is no longer a member and should be immune from congregational discipline.
I would love to see some of these issues resolved in a court of law, but I'm not optimistic that it will happen any time soon. The Witnesses seem to like ambiguity and the ability to make contradictory claims so they can use whatever defense has the best chance for success in a particular situation.