I have read of US court decisions involving other religions where the person resigned from the church while disciplinary proceedings were pending against them.
Some of those cases held that their resignations removed the church's jurisdiction over them unless they had agreed beforehand to church rules that allowed the disciplinary authority to continue proceed even after the person quit.
Those cases didn't involve shunning, but they did involve the church announcing a disciplinary decision against such an individual.
A few individuals won substantial verdicts against their church where they had not been shown to have consented to the church following such procedures.
A number of people in the Ray Franz purge had said, "I wasn't baptized into an organization."
I think the change was made to correct that "oversight."
I think it would be an interesting case if a JW could show that they were never told that a DAd or DFd person would be shunned.
I think it also explains why the WTS claims that the shunning is voluntary.
It's their way of relieving the organization of liability if someone challenges the shunning in court.
Just my opinion...