I understand why some people think that because the doctrines are nonsensical, WT legal policies must be foolish also, but I'm not sure that's the case. As with any big organization, the goal is not eliminating legal liability; that's not going to happen. The goal is to reduce exposures to a comfortably small percentage of revenue and to be able to budget for it. The large reliance on volunteers mostly, if not totally, eliminates employment law exposure. The proportion of JWs who the society is liable for on an agency basis is also smaller than most other religions. For example, if a Catholic Priest caused a car accident while driving around making visits to shut-in parishoners, the diocese would be liable since the Priest is an agent. For the society to be liable, it would have to rise to the level of a circuit overseer or bethelite doing the same thing - they would never be liable without their own negligence for elders or MS running around doing JW business. They also don't have formal counseling or children's programs, and no official elder or MS business involves any one-on-one time with children, so I am not sure that they would be liable merely for not conducting background checks. The only activity where one might be alone with a child would be field service, but that's not activity specific to being appointed - all JWs go in field service.
On top of all this, add the culture of JWs not feeling free to bring lawsuits against JW entities if they want to remain as a member. There is no way to know for sure, but I would be very surprised if Watchtower's average annual payout for legal settlements, judgments and liability insurance, as a percentage of total revenue, was not one of the lowest of all centrally organized religions in the U.S.