All they need is a shadow bank account in some offshore land where US government can't see the transactions. IMO if they can do it slowly overtime they will use BS excuses why they need to sell this and that asset, report increased expenses for missionaries and such if they have to report anything to the feds, while at the same time bloat a shadow account or a holding company offshore. I don't think they will shut the doors over night but very possibly cash in, in many places and make watchtower witness congregations squeeze into one building instead of two or three. Excuses can very with most likely BS story being that it being done for the benefit of the people who cannot affort the upkeep of all these building due to global crisis. As the crises continues to worsen they will continue making watchtower witnesses do with less and still try to fleece them at the conventions/assemblies which may end up being rented instead of being owned as they are now. I truely believe that this crises as it worsens will give GB one last excuse that the end is near and it will be a repeat of 1975 on a grander scale.
They have enough lawyers and accountants to know the ins and outs of the way of moving money around without getting caught - it can't happen over night and that's one drawback for them.