I wonder what excuses they are giving. It must be humiliating and embarrassing for the Bethel Branch brothers to have to explain why they don't feel they have a moral obligation to join the scheme.
Given that joining is voluntary, the Watchtower probably considers it impossible to join. If they voluntarily contributed funds as compensation for victims in Australia then they would have to do it on a worldwide basis. By joining they would be acknowledging that they did have a moral obligation.
I wonder if Australia is included in this November preaching campaign to Politicians and businesses? The letter does say it is a global preaching campaign. That will be so crazy given that many politicians know they wouldn't join the redress scheme.