In one cong I was in there was an elder who was looked up to by all. He had served a prison sentence early in the Viet Nam era for conscientiously objecting to military service (today he'd have the option of alternative service). He served on numerous JCs. Then one day he walked away from his wife, kids, and cong. He submitted a letter to BOE saying that he'd been carrying on an adulterous relationship for a long time with a worldly woman. He never returned to the org or his wife and kids. Yep, all his JCs decisions were still binding.
The WT org is not set up to do anything else. It would create a real mess for them to do otherwise.
Your statement "In a court of law of most countries that would be a grounds for appeal" calls to mind one of the reasons that the GB years ago shut down the Theocratic Attorneys and Doctors, an in-house JW org, once outside the purview of the GB. This group was mentioned twice in RF's CofC book. One of the things that was being discussed among them was the notion that certain important, basic aspects of Western jurisprudence and governance did not exist within the judicial system of the WTS. What a threat that was to the GB! Naturally they felt they had to shut the whole thing down.